File synchronization problems

Actual behaviour
Syncing problem.
I am not able to autoamtically synchronize files on my OC server.

Synching with local client (Ubuntu1 4.04 and Win 10) produces following errors

In Ubuntu terminal " sudo apt-get update " produces this message:

W: There is no public key available for the following key IDs:
W: Failed to fetch " 404 Not Found [IP: 80]"
W: Failed to fetch " 404 Not Found [IP: 80]"

E: Some index files failed to download. They have been ignored, or old ones used instead.

Log of the local ownCloud client produces this message:

  1. 09. 16 09:09:02, tablica_crkovanja.odt, ownCloud,Continue blacklisting: Error downloading " - server replied: Forbidden"
  2. 16 09:09:02, iso 9001.xls, ownCloud,The item is not synced because of previous errors: Error downloading " - server replied: Forbidden"
    (links and server name edited"

Was not able ti find a relevant solution so far. Please help me resolve this problem.


every known info about WebDAV issues (which you're having here) are collected at the documentation:

and at the following FAQ:

Please work your way through this resources and information how to identify the issue within your environment.