The error "not enough server storage available" is shown after a few days of use
When using SyncBack to synchronize / backup between two different computers, and UNC paths are being used, after a few days you may receive the error message Not enough server storage is available from Windows (or other programs) and a network connection error from SyncBack. To resolve this: modify your profile, enable Expert mode (via the Click For Options button), go to the Network\Advanced page, and change the option Do not disconnect from the network after the profile has run.
If this does not help, and/or is not applicable in the first place, it has also been reported that this syndrome can cause the same Windows error:
This link is supplied as-is / without prejudice - use at your own risk.