I have a raspberry pi 4 system which was running until yesterday. I have made a shutdown to prevent the system for damage because we had work on the energy system here.
After that i started openhab and it starts fine but … no one of my mqtt things can connect.
I didnt made a upgrade/update or anything else … how is that possible and what can i do that the mqtt units can connect!?
I would generally recommend to use IP addresses, as name resolution on local networks can be flaky. Sometimes its the computers/devices, and sometimes it’s the router. Reserved IP addresses are the only guaranteed approach.