Dear community, I’m facing problems with a nextcloud-instance using docker-containers on a virtual server after running smoothly for more than a year with several version-upgrades during this time. It’s my first post here 
Nextcloud version : 27.1.2 running in most recent docker environment
Operating system and version : Debian 10
The sync-client (Nextcloud on PC/Win10)
The issue you are facing:
Problem: Nextcloud cloud instance is not syncing some files anymore, these files are also not accessible via the Web-Interface either, what the other files are. All of the files are inside shared folders (One person has shared, 3 other group-members have write-access)
Is this the first time you’ve seen this error? (Y/N): Yes and it effects probably 10 - 20 files of several hundreds within different shared folders.
Steps to replicate it:
- Simply start a sync on any of the PCs of the group-members
- Or try to open the file via the webinterface, other files inside the same folder work
- It is also not possible to open older versions from the version-history
The output of your Nextcloud log in Admin > Logging:
Sync-Client: "500 Internal server error" on "GET https://nextcloud....."
What can I do to dig deeper into this?
Where is the apache-log when using a docker installation?
Help and hints are very appreciated,
Olli