Cannot connect to Calendar API: Google.Apis.Requests.RequestError The user must be signed up for Google Calendar.  Errors [ Message[The user must be signed up for Google Calendar.] Location[ - ] Reason[notACalendarUser] Domain[calendar] ]
This error occurs when migrating a suspended mailbox in G Suite. You must enable the mailbox in order to migrate.
Restore a suspended user
Note: Verfiying credentials will succeed. However, a migration will fail with the error. This error can occur when Google is the source or destination endpoint.