I suddenly got error 500 if I try to call my cyberpanel admin Url (on port :8090)
But not on *:8090/phpmyadmin
Last thing I did a day before was a Ubuntu system update with:
Becaue I had a snapshot from before my system update, I experimented a bit and could fix this issue in my case by doing an cyberpanel Upgrade to the same version with the official way:
I belive my database (or something else) was updated and some cyberpanel specific settings got lost by this update.
So my advice; Do a "upgrade" of cyberpanel installation to the same version if you have the Error500 on admin panel url.