How to Fix Gmail Not Receiving Emails | Gmail Help Support

# How to Fix Gmail Not Receiving Emails? To get instant solution call 1-866-719-1006 Gmail Help Center tollfree on Gmail not Receiving emails. Else thsi guide explains every reason Gmail may stop receiving emails and outlines detailed solutions for each issue. The following sections also include advanced troubleshooting steps, Gmail server behaviors, Google account configuration rules, and device-specific causes that interfere with incoming messages. If Gmail is not delivering messages to your inbox, is delaying mail arrival, or is silently blocking certain senders, this guide will help you identify the origin of the problem and restore full mail functionality. --- ## Why Gmail not Receiving Emails? Why Gmail Stops Receiving Emails and How Users Can Resolve It Gmail can fail to receive emails when account settings are misconfigured, storage is full, filters reroute messages, or Google’s automated security systems detect suspicious activity. Connectivity errors, outdated applications, browser inconsistency, incorrect MX records, and domain misconfigurations can also interrupt email delivery. Users can resolve these issues by reviewing inbox categories, checking storage capacity, confirming spam rules, removing incorrect filters, and ensuring that their devices and applications are properly synchronized. In more advanced cases, users may need to examine domain DNS settings, reset security preferences, or verify their identity within their Google Account. Gmail typically resumes normal delivery once the underlying issue is corrected. --- ### Why Gmail is important? Gmail’s reliability has made it one of the world’s most widely used email platforms, but it is not immune to delivery problems. Users sometimes discover that important messages never appear, are delayed for long periods, or vanish into hidden folders. Although these situations can be frustrating, they are usually caused by fixable settings, minor errors, or overlooked details. This article explores every known cause of Gmail delivery failure and provides a full set of practical and advanced solutions. --- ### 1. Confirm That Gmail Storage Has Not Reached Its Limit Gmail, Google Drive, and Google Photos all share the same storage quota. When the storage limit is reached, Google immediately stops delivering new emails. #### Why Storage Limits Affect Email Delivery Google allocates a fixed amount of storage (for free accounts), and once that capacity is exhausted, Gmail cannot save incoming messages. These messages may bounce back to the sender with a notification indicating that the mailbox is full. #### How to Verify Google Gmail Storage Usage 1. Open your Google Account storage page. 2. View the usage breakdown across Gmail, Google Drive, and Google Photos. 3. Determine whether large attachments, high-resolution images, or Drive files have consumed the available space. ### How to Free Storage on Gmail To restore mail delivery, users can remove unnecessary emails, delete oversized attachments, empty the spam and trash folders, or clear unused Google Drive files. Upgrading to a larger storage plan also resolves the issue immediately. --- ### 2. Check Spam, Junk, Promotions, and All Mail Folders Many users assume that missing messages never reached their Gmail at all, but Gmail’s sorting system may have placed them in other folders. ##### Why Messages Go to Spam Gmail uses automated classifiers that evaluate sender behavior, message content, user interaction patterns, and global spam signatures. Any suspicious elements may redirect the message to the spam folder. ##### Promotions, Social, Updates, and Forums Tabs If inbox categories are enabled, Gmail automatically distributes email into multiple tabs. Some important messages may not appear in the primary inbox. ##### How to Check Spam 1. to fix Gmail not Receiving Emails Open the Spam folder. 2. Explore the Promotions, Social, Updates, and Forums tabs. 3. Search for the sender’s email address using the Gmail search bar. 4. Review the All Mail section to determine whether a message exists in a non-primary folder. --- ### 3. Review Gmail Filters and Blocked Addresses Filters can silently redirect incoming mail, archive messages, or automatically delete them. ##### How Filters Affect Delivery When users create filters to organize messages, they may unintentionally set rules that skip the inbox. ##### How to Review Filters 1. Open Gmail settings. 2. Navigate to Filters and Blocked Addresses. 3. Inspect every filter for unintended actions such as deleting, skipping inbox, or forwarding messages. 4. Remove or modify any filter that interferes with proper delivery. ##### Blocked Senders Blocked addresses are automatically routed to spam. Removing an address from the blocked list ensures the user receives future messages. --- ### 4. Examine Forwarding Preferences and POP/IMAP Access Forwarding and POP/IMAP settings can pull emails from the Gmail account or reroute them elsewhere. ##### How Forwarding Causes Missing Messages If forwarding is enabled, Gmail may automatically redirect messages to another email address. If that address is misconfigured or inactive, the messages may appear lost. ##### POP Clients A desktop app configured with POP may download emails and remove them from the Gmail server, making it appear as though Gmail never received them. ##### IMAP Synchronization IMAP sync problems may hide messages in the local email app even though Gmail has received them correctly. #### How to Review These Settings 1. Open Gmail settings. 2. Go to Forwarding and POP/IMAP. 3. Disable forwarding unless necessary. 4. Ensure POP downloads are disabled or configured not to delete messages. 5. Confirm that IMAP is properly enabled. --- ### 5. Investigate Whether the Sender Is Receiving Bounce-Back Messages Sometimes Gmail is functioning normally but the sender receives an error message. ##### Possible Bounce-Back Causes 1. Invalid DNS configuration on the sender’s domain. 2. Gmail’s security filters blocking suspicious sources. 3. Temporary server issues from the sending provider. 4. Blacklisted IP addresses used by the sender’s mail server. ##### What to Request From the Sender Ask the sender to provide the exact bounce-back error code. This code reveals whether Gmail rejected the message or whether another server caused the failure. --- ### 6. Ensure Your Internet Connection and Browser Are Stable Although this may sound simple, connection instability frequently affects incoming messages. ##### Browser-Related Causes 1. Corrupted cache files 2. Conflicting browser extensions 3. Outdated browser versions 4. Security extensions that block Google scripts ##### Connection-Related Problems A weak or unstable network may cause Gmail’s interface to time out, preventing new messages from loading. ##### How to Fix 1. Try Gmail in a different browser. 2. Use incognito mode to rule out extension interference. 3. Clear cache and cookies. 4. Switch networks to test connectivity. 5. Update your browser to the newest version. --- ### 7. Disable or Adjust Gmail’s Confidential Mode and Sensitive Filters Some accounts use advanced settings that restrict message visibility. ##### How Confidential Mode Affects Emails If the sender uses confidential mode, messages may expire or require special decryption steps. ##### Sensitive Content Filters Users who have enabled high-security modes or special content blockers may inadvertently block legitimate messages. ##### How to Adjust Review advanced settings and remove any rules that suppress message content. --- ### 8. Check MX Records for Custom Domains (G Suite or Google Workspace) Users who run professional or custom domains often face issues with misconfigured DNS settings. ##### How MX Records Work Mail exchanger records determine where emails are delivered. If these records are incorrect, Gmail cannot receive messages for the domain. ##### Typical MX Misconfigurations 1. Missing Google Workspace MX entries 2. Incorrect priority assignment 3. Conflicting records from old hosting providers 4. Slow DNS propagation after recent changes ##### How to Fix 1. Access your domain registrar. 2. Add the official Google MX records. 3. Delete non-Google MX entries. 4. Wait for DNS propagation. --- ### 9. Investigate Google Account Security Alerts Google may temporarily block incoming messages if it detects suspicious account activity. ##### What Triggers Security Holds 1. Login attempts from unknown locations 2. Malware-infected devices 3. Suspicious automated activity 4. Credential leaks detected on the dark web ##### How to Restore Mail 1. Visit your Google Account Security page. 2. Review security notifications. 3. Verify your identity when prompted. 4. Reset your password. 5. Remove unauthorized devices. --- ### 10. Confirm That Gmail Servers Are Online Although rare, Google’s servers sometimes experience outages or temporary slowdowns. ##### How to Check Search for outage reports or review general web feedback. If a widespread outage is occurring, you must wait until services are restored. --- ### 11. Update the Gmail App on Mobile Devices Outdated mobile apps often lead to delayed or missing emails. ##### App-Related Issues 1. Outdated application version 2. Corrupted app data 3. Disabled background sync 4. Battery optimization preventing Gmail from checking mail ##### How to Fix 1. Update the app from your app store. 2. Clear the app’s data. 3. Reenable background sync. 4. Disable aggressive battery optimizations. 5. Sign out and sign back in. --- ### 12. Fix Device Notification and Sync Settings Messages may be delivered, but the device may not display them. ##### Android Sync Problems Android devices often disable sync when battery levels are low. ##### iPhone Mail App Issues Sometimes the native Mail app fails to sync properly with Gmail due to outdated token authentication. ##### How to Fix 1. Ensure auto-sync is enabled. 2. Reset account synchronization. 3. Remove and re-add the Gmail account. --- ### 13. Check If Your Account Is Under Manual Review by Google Some rare cases involve temporary restrictions while Google reviews policy compliance. ##### Common Triggers 1. Large mass email sending 2. Unusual login patterns 3. Terms-of-service violations ##### How to Resolve Users must comply with Google’s requests, such as verifying identity, answering prompts, or submitting documentation. --- #### 14. How to Fix Gmail not Receiving Emails Clear Browser Storage and Reauthenticate Outdated session data can make Gmail appear unresponsive. ##### Why Reauthentication Helps When session tokens expire, Gmail cannot load new emails, making it appear as though messages aren't arriving. ##### How to Fix 1. Clear cookies. 2. Log out and log back in. 3. Ensure multiple simultaneous sessions are not conflicting. --- ### 15. Remove Third-Party App Access Connected third-party apps may interfere with mail flow. ##### Examples of Interference 1. Automation tools moving mail 2. Productivity extensions blocking requests 3. Email-extraction tools causing security flags 4. Calendar syncing apps pulling data unexpectedly ##### How to Fix 1. Open Google Account permissions. 2. Remove apps you no longer use. 3. Revoke suspicious access. --- ### 16. Test Gmail on a New Device Sometimes the problem is device-specific and not Gmail-related. ##### Why This Works Testing Gmail on another device helps isolate whether the issue is account-related or device-related. --- ### 17. Review Google Workspace Admin Console (For Businesses) Administrators have additional settings that may block incoming mail. ##### Admin-Level Blockers 1. Email routing rules 2. Suspended user accounts 3. Quotas enforced by policy 4. Domain restrictions 5. Compliance rules 6. Gmail not Receiving Emails ##### How to Fix Gmail not Receiving Emails Admins must review their configuration and adjust settings accordingly. --- ### 18. Examine Gmail Delivery Logs Advanced users can review message trace logs. ##### What Logs Reveal 1. Delivery times 2. Rejections 3. Delays 4. Spam filtering actions 5. System errors 6. Gmail not Receiving Emails --- ### 19. Contact Google Support Users with Workspace subscriptions can request direct support for mail delivery issues. --- ### 20. If None of the Above Works 1. Recreate the Gmail profile on the device. 2. Reset browser environment entirely. 3. Export all mail and reset account settings. 4. Migrate the account if necessary. --- #### 21. Inspect Gmail Labs and Experimental Features Gmail once included “Labs” features that offered experimental tools. Some users still have older versions of these features active in their accounts. ##### How Experimental Features Cause Delivery Issues An outdated experimental setting can interfere with message rendering, inbox loading, thread handling, or label display. Although most Labs tools were deprecated, certain legacy accounts may still inherit behavior that disrupts Gmail. ##### How to Fix Open Gmail settings and disable any remaining experimental tools or advanced beta features. Afterward, reload the Gmail interface and check if new messages appear normally. --- ### 22. Resolve Problems Caused by Email Delegation Delegation allows another Gmail user to access your inbox. While this feature is useful for business accounts, it can cause message visibility issues. ##### How Delegation Interferes with Mail 1. The delegate may archive messages unknowingly. 2. The delegate may apply filters or labels without noticing. 3. A misconfigured delegation setting may hide certain mail threads. 4. Gmail not Receiving Emails ###### How to Fix Review the list of delegated users and remove any delegations that are not required. After removing unnecessary delegates, refresh Gmail and test message delivery again. --- #### 23. Check Archive Rules and Auto-Archiving Behavior Some users may accidentally enable automatic archiving rules. Archived messages do not appear in the inbox, making it seem as if they were never received. ##### How to Identify Auto-Archiving Search for the missing message in the All Mail folder. If it appears there without the inbox label, it has been archived automatically. ###### How to Fix Check your filters for the “Skip the Inbox” or “Archive It” action. Disable these actions to restore normal message visibility. --- ### 24. Investigate Conflicts Between Gmail and External Security Suites Antivirus and firewall tools often include email scanning modules. These modules can block Gmail scripts or interfere with server connections. ##### Common Security Suites That Cause Issues Certain programs aggressively block connections to Google services or intercept HTTPS traffic. This can result in delayed message retrieval or loading errors. ##### How to Fix Temporarily disable email scanning features in your security suite. If Gmail works after disabling these features, add Gmail to the exception list. --- #### 25. Determine Whether a VPN or Proxy Affects Delivery When users connect through a VPN or proxy, Gmail may treat the connection as unusual. ##### How VPNs Interfere With Gmail 1. Google may temporarily restrict login attempts. 2. Gmail may require account verification. 3. The interface may fail to sync properly. ###### How to Fix Disable your VPN or switch to a server in your own region. Reconnect to Gmail and verify whether messages load correctly. --- #### 26. Review Browser User-Agent Alterations Some privacy tools modify the browser’s user-agent to mask device identity. Gmail uses the user-agent to load certain interface components. ##### How User-Agent Changes Cause Issues If Gmail cannot detect the browser correctly, it may force a simplified interface. This mode sometimes fails to load new messages. ##### Fix Restore default user-agent settings in your browser. Reload Gmail to confirm that the standard interface appears. --- #### 27. Remove Old Gmail Offline Data Gmail Offline stores emails locally for access without Internet. Outdated offline data sometimes prevents the inbox from loading new messages. ###### How to Fix 1. Go to Gmail settings. 2. Open Offline settings. 3. Disable Gmail Offline. 4. Clear data stored by Gmail in your browser. 5. Enable Gmail Offline again if needed. --- ### 28. Investigate Whether Message Delivery Is Delayed Instead of Blocked Sometimes Gmail receives emails, but delivery is slow due to external factors. ###### Common Causes of Delays 1. Congestion on the sender’s mail server. 2. Domain authentication failures requiring retries. 3. Large attachments needing longer processing time. 4. Temporary rate limits imposed by Gmail. ###### How to Verify Review email headers for “Received” timestamps. This reveals whether the delay occurred before arriving at Gmail. --- ### 29. Fix Issues Caused by Google Group Settings If your Gmail receives messages through a Google Group, the group configuration may block messages. #### How Google Groups Affect Delivery 1. Group permissions may prevent messages from reaching inboxes. 2. Moderation settings may hold messages for review. 3. Posting restrictions may block certain senders. ###### How to Fix Visit the Google Groups console and review posting permissions, moderation rules, and sender privileges. --- #### 30. Correct Mistakes in Gmail’s Address Auto-Suggestions Gmail sometimes inserts incorrect suggested addresses when composing replies. If users accidentally save or autofill the wrong sender address, emails may never reach them. ###### How to Fix Delete incorrect suggested email addresses from Gmail’s autocomplete list. After clearing incorrect entries, ask the sender to resend their message. --- #### 31. Detect Email Spoofing or Impersonation Attempts Some attackers mimic legitimate addresses by altering a single character. Gmail may block these attempts or redirect them to spam. ##### How to Recognize Spoofing Examine the sender address carefully. Spoofed domains often appear nearly identical to real ones. ###### How to Fix Add legitimate senders to your contacts. Block or report suspected spoofing attempts. --- #### 32. Investigate Whether DMARC, SPF, or DKIM Issues Are Occurring Advanced users and businesses must ensure their domain uses proper authentication. ###### Why Authentication Matters If a sender lacks authentication, Gmail may flag messages as suspicious or reject them outright. ###### How to Fix Ask the sender to enable SPF, DKIM, and DMARC for their domain. Verified authentication dramatically improves deliverability. --- #### 33. Solve Problems Related to Gmail Labels Labels can hide messages if incorrectly applied. ###### How Labels Cause Confusion Some labels act like folders, while others behave like tags. If a message is moved to a label but not assigned to the inbox, it seems missing. ###### Fix Review label behavior and adjust rules to ensure that inbox assignment remains intact. --- #### 34. Check for Account Quotas and Sending or Receiving Limits Gmail enforces limits to prevent abuse. If these limits are reached, Gmail may delay or block new messages. ###### Common Quotas 1. Max emails received per day. 2. Max email size. 3. Max attachment size. 4. Workspace admin restrictions. ###### Fix Wait for the quota period to reset, usually within twenty-four hours. For business accounts, request a quota increase. --- #### 35. Review Whether the Sender Is on a Real-Time Blacklist Mail servers rely on global spam blacklists. If the sender’s server appears on one of these lists, Gmail may reject the email. ###### Fix Ask the sender to check their IP reputation. Once removed from blacklists, Gmail delivery should resume normally. --- #### 36. Examine Whether a Mail Loop Exists A mail loop occurs when two systems continually forward messages to each other. This can cause mail to fail silently. ###### Fix Disable redundant forwarding rules. Test incoming mail after removing overlapping configurations. --- ### 37. Fix Multi-Inbox and Priority Inbox Misconfigurations Gmail’s advanced inbox formats can hide messages unintentionally. ###### How These Settings Cause Issues If triggers for priority or custom inbox sections are too strict, messages are filtered away from the main view. ###### Fix Reset inbox type to default. Reintroduce advanced formatting only after verifying functionality. --- #### 38. Check Gmail API Limits Users who integrate Gmail with custom applications may hit API limits. When limits are exceeded, message syncing stops. ###### Fix Pause API requests until the limit resets. Optimize external scripts to reduce excessive calls. --- #### 39. Check OAuth Token Expiration for Connected Apps Apps that connect via OAuth require periodic reauthorization. Expired tokens prevent message syncing. ###### Fix Reauthorize the app via Google Account permissions. After authentication is refreshed, syncing resumes. --- #### 40. Investigate Server-to-Server TLS Issues When secure connections fail between mail servers, delivery may stall. ###### Fix Ask the sender’s IT team to confirm TLS handshake compatibility. Once resolved, mail flow should stabilize. --- ### How to Fix Gmail not Receiving Emails? #### 41. Verify That Your Domain Is Not Misconfigured After Migration Many email delivery failures begin after a domain migration to a new hosting provider. If a user recently transferred their domain, the old DNS settings may still be in place, causing Gmail to stop receiving messages. **Common Domain Migration Problems** 1. MX records still point to the previous host 2. TTL values are too high, delaying DNS propagation 3. Conflicting DNS entries exist from old services 4. The domain registrar applied default records that overwrite Google’s MX configuration **How to Fix** After migration, log in to the new DNS dashboard and compare every email-related record with Google’s official documentation. Delete all outdated entries and allow propagation time before testing new message delivery. --- #### 42. Identify Whether Your Hosting Provider Limits Email Delivery Web hosting providers occasionally restrict outgoing or forwarded mail from domain-based accounts. If Gmail receives mail through domain forwarding, the hosting provider’s limitations can interrupt delivery. ###### Why Hosting Limits Affect Gmail Some shared hosts restrict: 1. Daily outgoing email 2. Email forwarding 3. High-volume activity If limits are reached, forwarded mail may never reach Gmail. **How to Fix** Ask the hosting provider whether forwarding limitations or server throttling apply to your domain. Switching from forwarding to direct Gmail MX handling often resolves such issues. --- #### 43. Fix Conflicts Between Gmail and Legacy POP Tools Some legacy email tools still use outdated POP3 settings that interfere with Gmail’s modern architecture. ##### Why Legacy POP Tools Cause Issues Older applications may: 1. Fetch mail and delete it from the server 2. Use insecure ports 3. Fail to authenticate with modern security protocols **Solution** Upgrade the tool or disable POP access entirely. Switch to IMAP for real-time synchronization. --- #### 44. Evaluate Whether Gmail’s Smart Features Modify Incoming Messages Gmail’s smart classification, Smart Reply, and Smart Compose functions all rely on advanced machine intelligence. Occasionally, these features introduce classification changes that redirect messages. ##### How Smart Features Cause Confusion If Gmail misjudges the intent of a message, it may automatically categorize it into updates, promotions, or social tabs. **How to Fix** Disable smart features temporarily to determine whether they influence message placement. If disabling the features brings back missing messages, adjust classification preferences. --- #### 45. Consider Whether the Sender Uses Attachment Types Gmail Blocks Gmail rejects certain file types for safety reasons. If a sender attaches files such as executable formats, Gmail may block the message entirely. ###### Blocked Attachment Types Include Executable files, certain compressed formats, password-protected archives, and files containing macros. ###### How to Fix Gmail not Receiving Emails Request the sender to transmit files using alternative formats, such as cloud storage links. Once attachments comply with Gmail’s safety rules, delivery should succeed. --- #### Chapter 46. Investigate Whether Your Domain Has Expired When domain registration expires, all associated services—including email—stop functioning. Even if the Gmail interface appears normal, incoming messages routed through your domain cannot be delivered. ###### How to Fix Check domain renewal status. After renewing the domain, email delivery usually resumes, though DNS propagation may cause temporary delays. --- #### Chapter 47. Determine Whether a Temporary Gmail Lockout Has Occurred Google occasionally locks accounts temporarily due to suspicious activity. During this period, incoming email may be restricted. ###### Why Lockouts Happen 1. Excessive login attempts 2. Security alert triggers 3. Repeated incorrect password entries 4. Automated login attempts detected as bots ###### Fix Follow Google’s verification steps. Once identity is confirmed, Gmail restores full privileges. --- #### Chapter 48. Review S/MIME or Encryption Settings Some enterprise environments use secure encryption methods. If the sender or receiver is misconfigured, encrypted emails may fail delivery. ###### How Encryption Causes Issues 1. Expired certificates 2. Misaligned public keys 3. Incomplete encryption chains ###### Fix Update S/MIME certificates and ensure that both parties have compatible encryption settings. --- #### Chapter 49. Manage Google Workspace Routing Rules Workspace administrators frequently set routing rules to manage corporate email. Incorrect routing can cause emails to be discarded before reaching Gmail. ###### Fix Examine routing rules in the admin console. Remove or adjust rules that alter message flow unintentionally. --- #### Chapter 50. Confirm That “Send on Behalf” Settings Are Properly Configured If a user has permission to send emails on behalf of another account, incoming replies may be directed incorrectly. ##### Why This Matters Replies may go to the delegated address instead of the primary account, creating the illusion of non-delivery. ##### Solution Correct reply-to settings and verify addresses used during delegation. --- #### Chapter 51. Investigate Whether Gmail Is Limiting Attachments Gmail enforces strict limits on message size. If a sender attempts to send large files, Gmail may block delivery. ###### Maximum Sizes Message limit: approximately twenty-five megabytes Attachments exceeding this size should be uploaded via Drive. ###### Fix Ask the sender to compress the attachment or use cloud storage links. --- #### Chapter 52. Identify Whether Filtering Rules on Mobile Devices Override Gmail Some smartphone manufacturers include built-in spam or message filtering tools. These tools sometimes override Gmail’s native behavior. ###### How Mobile Filters Cause Missing Mail 1. Device-level blocklists 2. System spam filters 3. Local filtering rules in third-party apps ###### Fix Disable device-level filters and rely exclusively on Gmail’s filtering system. Restart your device after clearing filters. --- #### Chapter 53. Analyze Google Workspace Compliance Rules Compliance features are used to enforce organizational policies. These rules may stop emails containing sensitive information, even if legitimate. ###### Examples of Compliance Triggers 1. Certain keywords in sensitive industries 2. Identifiable personal information 3. Attached confidential data ###### Fix Modify compliance rules that unintentionally block legitimate emails. Consult your organization’s compliance officer if needed. --- #### Chapter 54. Investigate Email Throttling by External Senders The sender’s mail server may intentionally slow delivery due to server load or anti-spam measures. ###### Why This Happens Large bulk senders occasionally throttle outbound messages to avoid triggering spam filters. ###### Fix Ask the sender to inspect server logs. If throttling is detected, they must correct their sending practices. --- #### Chapter 55. Check If Gmail Has Flagged Your Address for Possible Abuse If Gmail suspects that your address has been compromised or used for spam, it may temporarily restrict incoming mail. ##### Common Abuse Indicators 1. Strange outgoing messages you did not send 2. Contacts receiving spam from your address 3. Login attempts from unknown countries ###### Fix Change your password immediately. Enable two-factor authentication. After securing the account, Gmail typically restores normal delivery. --- #### Chapter 56. Determine Whether MX Priority Is Set Incorrectly Even if MX records are present, incorrect priority values can disrupt mail routing. ##### Why Priority Matters Mail servers check MX records in order of priority. If the top-priority record is incorrect, messages may fail before reaching functional records. ##### Fix Ensure that Google’s MX records are configured with the correct priority numbers. Remove inactive competitor records. --- #### Chapter 57. Review Your SPF Record for Alignment Problems SPF (Sender Policy Framework) verifies which servers can send mail from a domain. Incorrect SPF alignment can cause Gmail to reject messages. ###### Fix Ask the sender to validate their SPF record. Once alignment is proper, delivery improves significantly. --- #### Chapter 58. Identify If a Large Number of Automatic Replies Has Triggered a Limit Gmail limits the rate of automatic replies, such as out-of-office messages. ##### Why This Causes Delivery Issues If limits are exceeded, Gmail may pause certain account functions temporarily, including receiving new mail. ##### Fix Turn off automatic reply systems. Once activity normalizes, Gmail will restore full functionality. --- #### Chapter 59. Ensure That Google Vault Retention Rules Do Not Override Your Inbox Organizations that use Google Vault may have retention policies that archive or delete messages before they reach the inbox. ###### Fix Work with your Workspace administrator to adjust retention timelines or modify preservation policies. --- #### Chapter 60. Investigate Whether Gmail Is Blocking Mail Through Advanced Spam Heuristics Gmail uses sophisticated heuristics that analyze global mail patterns. Sometimes, legitimate senders become caught in these systems. ##### Fix Ask the sender to check for unusual content in their messages. If necessary, whitelist the sender, add them to contacts, and mark any prior messages as “Not Spam.” ---