More than a week ago we rolled out an update to duplicacy.com to fix a non-user related issue in our Google Drive token handler. Unfortunately this update introduced a bug that caused the token expiration time to be set to 0. As a result the Duplicacy CLI would never attempt to refresh the token (as opposed to the requirement that it must be refreshed every hour), and Google Drive would then return Error 401: Invalid Credentials, authError after the token expires. This bug only affected users who downloaded the gcd-token.json file in the past week.
This bug has now been fixed. It is a server-side only fix so you don’t need to do anything.