Could not connect to server. NSURLErrorDomain - 1004

Hi all, today a German ISP hat a major outage and I was affected by it. Since then, i can‘t reach my HA. I get the „Could not connect to server.
NSURLErrorDomain - 1004“ error in any app. If I try to connect through the local IP I get „Die Website ist nicht erreichbar (German for Website could not be reached)

192.168.178.140 ist momentan nicht erreichbar.
ERR_CONNECTION_FAILED“ However, the RasPI is online, I see it in the router and I can ping it in the local network, In Nabu Casa, it says „The instance is not connected“. But I can‘t even open HA locally, although it is online and has an IP.

I of course have already restarted the whole Network and the RPi several times.

DNS issue? Your ip could be changed.

My IP resets every 24h anyway, but in case that is the case, how do I fix it? And why would it effect the local IP?