Hello,
I wanted to briefly describe an observation, in case someone should also get such a problem: I lost the web interface in a strange way. My sensor runs outside, but reasonably protected since December 2020 without problems and sends its data to the project.
A few months ago I started reading the data via the API and transferring it to homeassistant. A few days ago I noticed that no more data arrives in homeassistant. After that I noticed that the webinterface is not reachable anymore. Also the display was off. Powercycle didn’t help, after that it sends data to the project again, but I can’t reach it locally via the API or the webinterface and the display stayed off. When I read the serial port, I see the data being read out etc, but it’s clear as long as they’re still uploading.
Upon closer inspection, the contacts on the display were a bit rusty. After I disconnected the display and rebooted, everything worked again.
Learning: if something is wrong with the contacts, strange things can happen in other places.
If anyone can tell me why this is and how it’s related (or was it more of a strange coincidence), I’d be very excited to learn some more 
Cheerio
Arne
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