Troubleshoot
less than a minute
| Symptom | Likely cause | Resolution |
|---|---|---|
| CONNACK 0x95 “Packet too large” | Broker rejects the packet size. | Reduce payload size or set max_packet_size in the MQTT 5 CONNECT properties. |
| No incoming PINGRESP | Application traffic is more frequent than the keep-alive interval. | This is expected — the broker resets the timer whenever data flows. |
| Retained message not cleared | Message published without clearing retain flag. | Republish the same topic with an empty payload and --mqtt_pub_retain. |
| TLS handshake fails | CA bundle missing or host-name mismatch. | Verify --ssl_ca_file or (for tests) add --ssl_allow_untrusted. |
| Session resume not working | --mqtt_clean_start flag still set. | Omit --mqtt_clean_start and set a non-zero --mqtt_session_expiry_interval. |
Tip
Use--print_hex_bytes to view raw payload bytes when debugging encoding issues.Was this page helpful?
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