I had a problem, which I just want to mention, that somebody has a chance to have a look at it and potentially can contribute, that the problem does not come up again.
I have a nextcloud hosted at my hosting provider futris.net.
For quite some weeks, I synchronised my calender, tasks and files between my phone, tablet (both android, davx5 app) and pc (caldav synchroniser plugin in Outlook).
The last changes I remember were two files I worked with on all devices and started synchronisations manually, because I wanted to see the changes on the other devices. And two appointments added to the calender on the tablet.
This wednesday morning, my mobile devices (phone and tablet) came up with continuous error messages by the android davx5 app, that there was no connection to the cloud. It was also not possible to login via PC and browser. The error message there was
“Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
…
Additionally, a 500 Interner Server Error was encountered while trying tu use an ErrorDocument to handle the request.”
Since I was asked also to check the server, I contacted my hosting provider, who finally could solve the problem (as one try, they also updated from 18.04 to 18.06):
" das Update war nicht das Problem.
Wir haben das Update installiert und anschließend noch Ihre Installation von SQLite Datenbank auf MySQL umgestellt, da das bei vielen Dateien und mit den Clients sehr viel schneller läuft.
Das hatte aber zunächst auch nicht geholfen. Nun haben wir noch den PHP Modus von FastCGI auf Apache-FPM-Modul umgestellt und das hat das Problem gelöst.
Warum es mit FastCGI nicht ging, kann ich leider nicht genau sagen, da keine Einträge ins Log geschrieben werden. Aber es geht wieder."
Changing a php mode is nothing, I have ever heard before of. Even less of fastcgi or apache-fpm-module …
I like Nextcloud, because I could install it myself and it worked for some months without problems. I could manage to solve one problem during an update (via deleting a file via ftp mentioned in the update process). But this problem was far above my capabilities …
Hope that somebody reads this, checks the code and finds a way to make nextcloud even more stable 