Just setting up a lab XG and no matter what I try - Email notifications are not working. I have tried the internal mail server option, 365 account with App Password & finally 365 Direct Send.
Nothing appears in quarantine on the receiving mailbox side.
Has anyone else had similar issues? Running v19 - Build 317
So Notification with O365 are not supported.
See: https://docs.sophos.com/releasenotes/index.html?productGroupID=nsg&productID=xg&versionID=19.0 Known Issues:
Configure an intermediate relay to workaround this behavior.
What you can do instead: Central Management offers a Email Notification system as well. Simply register your firewall to Central and use the Notification System there.