gmail/oauth fails with maxconnections > 1 in v8.0.3 #250

I upgraded offlineimap from v8.0.1 to v8.0.3 and was no longer able to sync with my gmail.com e-mail. It would fail with an authentication failure error (imap: Socket dead after XOAUTH2 failure, aborting remaining auth methods). I had maxconnections = 2 but when I change it to maxconnections = 1 (or run offlineimap with -d imap logging) it succeeds. I am able to separately get refresh and access tokens using an independent program (whhich is called via oauth2_refresh_token_eval for offlineimap).

Maybe it's kind of race condition somewhere when two threads try to do OAuth at the same time? I wonder if it has something to do with the change in #244 ? I don't know enough to trace exactly what's happening, but perhaps the answer will be obvious to the maintainers.

This is offlineimap 8.0.3, imaplib2 v3.06, Python v3.14.5, OpenSSL 3.6.2 7 Apr 2026; macOS 26.5, M1 MacBook Pro.

And thank you for this wonderful program.