MQTT not listening...?

[Foxis (Dan)]

I have had an MQTT setup for quite some time. After updating to 2024.10.4, it doesn’t seem to receive packages from EMQX any more. It is connected to EMQX, and can publish messages succesfully. However, it doesn’t receive or handle messages.
In the frontend, simply clicking “start listening” will not display anything at all, not even the birth message from the MQTT listener. The area below the “start listening” choice is blank.

I have attempted to debug, but I get no meaningful errors. Debugging seems to indicate that it is listening, but in practice nothing shows up. I use MQTT explorer to publish messages to the broker, and those do not get through to MQTT in HA even though it is listening and subscribed to all topics.

Any ideas what to test? I have restarted, deleted the integration entry… I am at a loss.

Many thanks in advance!

[Foxis (Dan)]

Well, I solved the problem.

It turns out the config choice of “enable discovery” can really mess things up. With that option enabled, the HA MQTT integration sets up a bunch (~10) subscriptions at the broker, but will not listen to any manually configured subscriptions any more. Even any subscription created with the “listen to topic” function in the config pane will be ignored.

So, in my case, simply disabling the automatic discovery solved my problem. My manually configured subscription started working again and the “listen to port” function in the config pane can now be used to debug stuff.

Not sure if this is a bug or poor design, but it cost me about 4 hours today… Yay!

Hope this can help someone else.