Thanks for the reply. The cron job is configured (Windows task manager) and when I set the logging to 'debug' I see a log entry for it running: "Cron job executed [CLI]".
The Redirect URL set up in the email config within OSTicket is to a URL that is valid for the new machine as the DNS entry was updated to point that URL to the new server.
Can you tell me which tables store the OAUTH2 information? I want to compare the old and new databases to make sure everything is identical.
EDIT: I found this in the email_account table:
Last_error_message = "Credentials: Required option not passed: "access_token"