Time Machine stopped working to Synology NAS

I was haunting for the root cause of this issue for a long time.

A first backup to the NAS was working but incremental backups failed always. Backups to local medium were no issue either.

Based on a post here I found the solution. Ensure that the NAS is configured to use SMB NOT AFP. That did the trick for me. The enoying situtaion that a only can do backups if I reconnect the medium on the NAS every time if I want to ensure I have a backup is gone.

Just to let Synoglogy NAS users know... Ensure SMB only and you are good!