HTTP Error 500 2 days after Ubuntu update

A weird thing happend. All of a sudden today my Nextcloud stopped working and when i tried to call up the login page i was greeted by a HTTP 500 error.

Past Saturday i did an upgrade to 16.04.3 and after the upgrade and a reboot everything was still working.
Fast forward to today and this morning it still worked fine. But round about 14:00 it suddenly stopped.

The server on which it is running had to be rebooted a few times today so that prob has something to do with it.

So let me list what i have:

Nextcloud is running in HyperV 2016 as an Ubuntu 16.04.3 LTS server.
Nextcloud version is 12.0.0

I’m not sure where to look atm. This feels like an Apache thing but i would not know where to start.

First place to check is the apache-logs.
Are ALL the directory and file-perms correct?
Is the php-installation fully functional? Cann you run the occ-command?
Was apache upgraded, too? I think there was a major change in the apache-modules-syntax between one of the 2.4.2X-versions.

GOOD LUCK!

Apache errors led me to PHP errors which led me to Mysql erros. The Mysql server would not start for some reason. Just stopped at a random point in the day.
Tried all sorts of fixes regarding the error i saw but the general consent was to reinstall mysql.

Since it came out of nowhere i have no faith in the upgrade and decided to roll back to a backup 2 days ago before i did the update.
No problems now and i’ll prob will not update Ubuntu anytime soon :smiley:

Thnx anyway :wink:

GOOD LUCK then!
(sometimes one has to run mysql_upgrade ot sth. like it after an upgrade.)

I might do that at a later time. I’ll clone the VM first so i can test it without anything going wrong.
Just find it weird it happend 2 days after and in the middle of the day.