EddieHooks
It’s never wise to use a distribution list as a system email (especially if any agent email is on the list). It can cause serious looping issues, excessive alerts, etc. With that being said if you want to take the risk you can add a real account (you can authenticate as) to the Send As and Read and Manage permissions on the distribution list email (via exchange admin center) and when you configure OAuth2 authentication for the email uncheck Strict Matching and authenticate as the user you added to the Distribution List permissions. The strict matching setting sometimes doesn’t save the first time and you may see an error saying there is an email mismatch but if that happens simply click Config uncheck it again, resubmit, and all should be good.
Cheers.
