Very strange behavior in Hassio

Anyone have an idea where I can start to solve this issue. Since yesterday I have a lot of issues with my HA running on a RPi 4.

I cannot connect to my HA anymore using my duckdns URL (doesn’t work in browser, HA Ios app, etc). The only thing I can now access when logging into HA from my local network is the lovelace pages. From my floorplan tab in lovelace I can still turn lights on and off by clicking. But all other functionality seems to be down. “Energy”, “Map”, “History”, “Logbook”, nothing seems to be working anymore…

I can click “Settings” and see the settings page, but I cannot click any of the buttons here either. At least, I can click, but nothing happens…

Anyone has an idea where to start debugging this?

And now after a reboot it is back!

Can anyone point me where to start searching what happened?