---
# System prepended metadata

title: IE-343 (TrackingID#2204110050002352) Failing C2D subscriptions

---

# IE-343 (TrackingID#2204110050002352) Failing C2D subscriptions

Device log:

```
Apr  5 13:00:50 Drv.mqtt: MqttDrvSendConnect() >>> CONNECT
Apr  5 13:00:50 Drv.mqtt: MqttTcpSendFrame() send 351 bytes, type = 0x10
Apr  5 13:00:50 Drv.mqtt: MqttTcpOpenConnection()   --- CONNECTED ---   host:<iot-ingest-io-dev.azure-devices.net>   port:8883   socket:12
Apr  5 13:00:51 Drv.mqtt: MqttTcpWrite() SSL written:351   (size:351)
Apr  5 13:00:51 Drv.mqtt: MqttDrvSetFailure()
Apr  5 13:00:51 Drv.mqtt: MqttTcpHandleInput() SSL read 4 bytes
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() header type: 20
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 20 02 01 00              |  ...
Apr  5 13:00:51 Drv.mqtt: MqttDrvInputConnack() <<< CONNACK
Apr  5 13:00:51 Drv.mqtt: MqttDrvCheckInput() <<< CONNACK
# TCP and MQTT connection are established now, let's subscribe for cloud-to-device messages:
Apr  5 13:00:51 Drv.mqtt: MqttDrvSendSubscribe() >>> SUBSCRIBE <devices/mbs-poc-4014e357-7302-41cc-8970-692120cae525/messages/devicebound/#>   (id:7)
Apr  5 13:00:51 Drv.mqtt: MqttFrameSubscribe() SUBSCRIBE <devices/mbs-poc-4014e357-7302-41cc-8970-692120cae525/messages/devicebound/#>   (Q:0   id:7)
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() header type: 82
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 82 50 00 07 00 4B 64 65  | .P...Kde
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 76 69 63 65 73 2F 6D 62  | vices/mb
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 73 2D 70 6F 63 2D 34 30  | s-poc-40
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 31 34 65 33 35 37 2D 37  | 14e357-7
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 33 30 32 2D 34 31 63 63  | 302-41cc
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 2D 38 39 37 30 2D 36 39  | -8970-69
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 32 31 32 30 63 61 65 35  | 2120cae5
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 32 35 2F 6D 65 73 73 61  | 25/messa
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 67 65 73 2F 64 65 76 69  | ges/devi
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 63 65 62 6F 75 6E 64 2F  | cebound/
Apr  5 13:00:51 Drv.mqtt: MqttFrameShow() 23 00                    | #.
Apr  5 13:00:51 Drv.mqtt: MqttTcpSendFrame() send 82 bytes, type = 0x82
Apr  5 13:00:51 Drv.mqtt: MqttTcpWrite() SSL written:82   (size:82)
Apr  5 13:00:51 Drv.mqtt: MqttDrvSetFailure()
Apr  5 13:00:51 Drv.mqtt: MqttTcpHandleInput() SSL read 0 bytes
Apr  5 13:00:51 Drv.mqtt: MqttTcpHandleInput() SSL read failed with size:0 (error:00000005:lib(0):func(0):DH lib)
# oh, IoT Hub closed the TCP connection (that we can see in the packet dump). But why?
Apr  5 13:00:51 Drv.mqtt: MqttDrvBrokerInput() invalid parameter!   (frame:0   size:0)
Apr  5 13:00:51 Drv.mqtt: MqttDrvSetDisconnect() subscribe:1   publish:0
Apr  5 13:00:51 Drv.mqtt: MqttTcpExit()
Apr  5 13:00:51 Drv.mqtt: MqttTcpCloseConnection() close socket:12
Apr  5 13:00:51 Drv.mqtt: MqttTcpCloseConnection()   --- DISCONNECTED ---
Apr  5 13:00:51 Drv.mqtt: MqttTcpCloseConnection() close socket:-1
```