Randomly MQTT connection gets closed with error transport_read(): EOF (IDFGH-17049)

[aggaddam]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

The MQTT client connection gets randomly disconnected while publishing/streaming data to mqtt broker over TLS, sharing device logs. Could anyone figure out if this issue is related to the broker side or the client side?

Environment:
ESP-IDF version: v5.4.1
Hardware: ESP32-C3

Logs:
E (4559962) mqtt_client: esp_mqtt_handle_transport_read_error: transport_read(): EOF
E (4559962) mqtt_client: esp_mqtt_handle_transport_read_error: transport_read() error: errno=119
E (4559969) MQTT_S: MQTT_EVENT_ERROR
E (4559973) MQTT_S: Last err code reported from esp-tls: 0x8008
E (4559979) MQTT_S: Last tls stack errno: 0x0
E (4559984) MQTT_S: Last captured errno : 0 (Success)
I (4559990) MQTT_S: esp_mqtt_task stack usage percent = (56)
E (4559997) mqtt_client: mqtt_process_receive: mqtt_message_receive() returned -2
E (4560007) MQTT_S: MQTT_EVENT_DISCONNECTED, Reason: 0, 1

[bogdankolendovskyy]

Hello @aggaddam,
The error seems to be caused by broker cleanly closing the connection, do you have access to broker logs to see the reason for disconnection ?
Thank you.

[allopatin]

I'm currently debugging the issue on ESP32-C3 with IDF 5.3.4. We just checked logs on our EMQX brokers and there were no errors. Timestamps align between both logs. We see the regular PINGREQ -> PINGRESP ping pong and then a regular CONNECT from the ESP32 (which is forced be the mqtt_client component). Keep alive is not violated. On ESP32 side above error is reported but no further info is provided if debug logs are enabled.

The following debug logs are enabled:

esp_log_level_set("wifi", ESP_LOG_DEBUG);
esp_log_level_set("esp_netif", ESP_LOG_DEBUG);
esp_log_level_set("esp_netif_lwip", ESP_LOG_DEBUG);
esp_log_level_set("esp_netif_handlers", ESP_LOG_DEBUG);

Maybe I'm missing some components but it's tough to find the correct logging components as they're not really documented from what I was able to find.

Edit: Logs
ESP32:

D (103251634) mqtt_client: Sent PING successful
D (103251644) mqtt_client: mqtt_message_receive: first byte: 0xd0
D (103251644) mqtt_client: mqtt_message_receive: read "remaining length" byte: 0x0
D (103251646) mqtt_client: mqtt_message_receive: total message length: 2 (already read: 2)
D (103251655) mqtt_client: msg_type=13, msg_id=0
D (103251659) mqtt_client: MQTT_MSG_TYPE_PINGRESP
E (103276586) mqtt_client: esp_mqtt_handle_transport_read_error: transport_read(): EOF
E (103276587) mqtt_client: esp_mqtt_handle_transport_read_error: transport_read() error: errno=119
E (103276595) c_mqttInstance.cpp: [0]: Time: 2026-01-21 14:12:04
W (103276600) c_mqttInstance.cpp: [0]: Broker closed connection
W (103276607) c_mqttInstance.cpp: [0]: Last esp-tls error: 0x8008
E (103276613) mqtt_client: mqtt_process_receive: mqtt_message_receive() returned -2
D (103276624) mqtt_client: Reconnect after 10000 ms
I (103276795) mqtt_client: Client asked to disconnect
W (103276796) c_nvsmanager.cpp: key broker_0 does not exists in nvs
I (103276998) c_mqttInstance.cpp: [0]: Stopped

Broker:

2026-01-21T14:11:39.601360+00:00 [MQTT] {device}@{broker} msg: mqtt_packet_received, packet: PINGREQ(Q0, R0, D0), username: {username}
2026-01-21T14:11:39.601499+00:00 [MQTT] {device}@{broker} msg: mqtt_packet_sent, packet: PINGRESP(Q0, R0, D0), username: {username}
2026-01-21T14:12:10.606796+00:00 [MQTT] {device}@{broker} msg: mqtt_packet_received, packet: CONNECT(Q0, R0, D0, ClientId={client} ProtoName=MQTT, ProtoVsn=5, CleanStart=false, KeepAlive=120, Username={username}, Password=******, Will(Q1, R0, Topic={topic_tree} Payload(text)=...(130 bytes))), username: {username}

[aggaddam]

Hello @aggaddam, The error seems to be caused by broker cleanly closing the connection, do you have access to broker logs to see the reason for disconnection ? Thank you.

After debugging, this issue appears to be with the MQTT Broker.

[allopatin]

Hello @aggaddam, The error seems to be caused by broker cleanly closing the connection, do you have access to broker logs to see the reason for disconnection ? Thank you.

After debugging, this issue appears to be with the MQTT Broker.

Are you using an EMQX broker by any chance?