With my problem I did the same. In the MQTT handler I restart the wi-fi connection.
It is not the perfect solution, but I don’t have a better idea.

I would say, welcome to the unsolved mystery club. I had a few tries with a similiar approch like you did. (I made a fall back mechanism when the wi-fi is unavailable) I solved my issue with starting AP and STA mode separaretly. Before each start/init of a mode I deleted the mode that I no longer us...

A quick update on the mqtt problem. It happend again with no visable Wifi error. And no error in the mosquitto log. I always try to foolproof my code, so I tried to manually stop my MQTT and see what's happend. Manually: I (206506) mqtt: MQTT_EVENT_BEFORE_CONNECT E (206506) esp-tls: [sock=54] delaye...

I don't want to do anything like this. I plan to use this in an environment with a wifi router and an MQTT server hosted locally or over the internet. Nothing more.

Finally I was (or the nature was) able to reproduce the error. So my village have frequent power outage, only for 2-3 seconds. This interval is enough to restart my WIFI router, but it is not able to shutdown my ESP nor my MQTT host, because these are running on an UPS. Today I was working on my ESP...

I added warning and error logging for the future to my mosquitto. We will see.
But it is only happening with this code. I am running another very simple code without tasks. That is going for more than 2 day now.

I removed the 2 lines from my mqtt conf that you mentioned, going for another test.

I have my own server running in a docker, on local hardware. I mentioned it earlier.
I want to debug this issue.

Do you mind giving me a proper mqtt config that is working as expected ?
Maybe this is the problem.

Then the TAG of the error message is misleading.
Which direction should I go in debugging?
Should I set more parameters in MQTT config?

Where should I look for it?
At my host that runs mosquitto ? Or in my ESP mqtt configuration ?
I reckon I don’t use TLS, because in MQTT Explorer where I monitor topics, messages, etc I disabled the TLS connection.

Side note:
I did a test again without task halt and it failed in about 8 hours.