I've been using the Pro version of the app for years and for the last several days my mobile app was not syncing with the online account at https://deliveries.orrs.de/sync/#
So I tried to revoke my Google account access in Settings-->Synchronization, and when I tried to re-connect my Google account it says "Error. Account already exists." I am not trying to create new account, only to sign into my sync account using my Google account like I've always done. Yet, it seems like the app is trying to create a new account instead of sync my existing one. I've been able to set up the app on new devices before without issue.
I also tried uninstalling the app and re-installing it, but the same issue occurs.
What can I do to resolve this? I searched your support site and found several posts of people with the same issue but no confirmed resolution.