Syncdocs works for my gmail account just once (files are synced ok) and then pauses. I have to start it again each time to sync more changes.
In the log I see the following pattern repeating:
4/14/2017 9:57:51 PM(ver. 6.931) InitContacts Contacts will not work
Execution of request failed: https://www.google.com/m8/feeds/contacts/default/full?max-results=9999 Google.GData.Client.GDataRequestException : sd criticality=1
Inner: System.Net.WebException: The remote server returned an error: (401) Unauthorized.
Source: Google.GData.Client : sd criticality=1
Solution (thanks Andrew):
The problem is caused by you revoking Syncdocs' permissions to sync your contacts (or by it having been revoked for some other reason).
You can either disable contact syncing by unchecking "Backup contact list once a day" (this will get rid of the error but would not sync) or re-authrize it by entering the "Syncdocs Preferences" screen, clicking on the "Account" tab and clicking on the "Re-authenticate" button.