I am on Fedora 33 and I have added my GMAIL account to the Online Accounts. The GNOME Calendar application can sync with my Google Calendar and the GNOME Contacts application can sync with my Google Contacts. So, everything works fine.
I then installed the Evolution email client and it picks my GMAIL account from the Online Accounts so it properly syncs my Google email and calendar. However it fails to sync my Google Contacts producing the error message:
The address book backend servicing “Contacts” encountered an error.
The reported error was “The content of a <gContact:event/gd:when> element (‘0000-08-15’) was not in ISO 8601 format.”.
Is this a problem that others are also experiencing? Is there a solution?
Unfortunately I can’t test to that as I don’t have Google contact sync enabled, but the message points me into the direction that one of your contacts, has wrong date format for either birthday or some other kind of anniversary assigned to it.
Could you locate contact that has some kind of anniversary or birthday at 15th of August and try adding a year to it or something to see if this will fix the issue?
I’d say this could be the issue somewhere in the Evolution services.