This issue is reported as resolved, and we have not had any new cases reported on campus this week. From Microsoft:
"Final status: Our fix to revert the affecting update has completed and we've confirmed via telemetry that message traffic has been restored, confirming impact resolution.
Scope of impact: This issue impacted some users attempting to send email messages via the Outlook desktop client and Outlook on the web.
Start time: Monday, July 11, 2022, 7:00 PM (7/12/2022, 12:00 AM UTC)
End time: Saturday, July 30, 2022, 1:00 PM (6:00 PM UTC)
Root cause: A recent update intended to optimize traffic load balancing and improve email transport times introduced a code issue that lead to impact.
- We're reviewing our update validation and testing procedures to better understand how the code issue was missed to better prevent similar future impact."