OAuth support for accessing GMail or O365/outlook.com mailboxes using modern authentication is currently not available for FogBugz. It is available for logging in your users to FogBugz, but not for logging in to external Mailboxes like GMail or O365/outlook.com/Exchange Web Services (EWS).
Microsoft have confirmed that Basic Authentication can be re-enabled for a protocol in accounts for use after the 1st October deadline. It will continue to be available until the end of December 2022. Further details can be found in this MS article.
Fogbugz customers using Exchange Online should opt-out from disabling Basic Authentication or re-enable Basic Auth if required.
The request for adding OAuth as a supported authentication type for FogBugz mailboxes has been shared with our product team and will be delivered prior to the end of December 2022. Subscribe to our Release Notes for updates to be informed when it becomes available.