thingspeak server closing connection immediately

mqtt3.thingspeak.com closing the connection immediately when trying to connect using A6 gsm module. Has been working flawlessly up to a week ago.Not able to publish any data to private channel. No encryption used (http).

Answer 1

[Christopher Stapels]

Usually that means an authentication issue. Can you ensure the device is set up correctly and it is allowed to publish to the channel you are trying to write to? It is easy to make an inadvertant change in the MQTT interface.

[Sven Ottosson]

Thanks for the answer, all has been working fine for months until a few days back. Tried another user/pass but still same problem. I can publ subscribe from another client without problems so something else must be at fault. T/S in progress

[Christopher Stapels]

Here are a list of troubleshooting tips. Sometimes a change inyou device local MQTT sessings can casue the broker to reject a connections, for example setting last will. It might even happen inadvertantly with a library update. A library update recently broke my ESP-now project. :(

Answer 2

[Vinod]

Are you able to publish/subscribe to the channel updates from a different client such as MQTTX ? If that works, I would suggest looking into the code running on your device. Maybe try switching from the GSM modem to a WiFi network. Does that work? If so, you can have localized the problem to the A6 module.

[Sven Ottosson]

Thanks for the reply, yes I can publish subscribe from another client. It points to some other issue.

[Vinod]

Thank you for confirming, Sven.

Could you please post the resolution and how you narrowed down the issue so it may help the next person who has a similar issue?