Hi Shutterlab,
Sorry to hear about your difficulties. Are you seeing the server error in a browser or within the Creative Cloud app? I have seen instances of this error occurring in the past when collaborating a folder with others and one of the collaborators runs out of space. Once this occurs, anyone which attempts to sync files within the collaborated folder would receive a server error message, not just the collaborator.
You can check if you have collaborated folders by going to this web address:
https://assets.adobe.com/files?filter=shared
If you do see folders at that web address that means you have collaborated folders. I'd check to see if the files which are resulting in the server error are within a collaborated folder.
If you do have collaborated folders, you might want to ensure who ever you are collaborating with has free space:
https://assets.adobe.com/activity/settings
and recommend that they empty their online archive here:
https://assets.adobe.com/files?filter=archive
Please let me know if this helps,
Thanks,
- Dave