Sending, receiving, and organizing email in Outlook.com
Unfortunately that's likely due to the ongoing service-side outage. You can monitor the latest updates regarding today's Outlook outage via Service Health in Microsoft 365 Admin Center referencing the incident ID: MO1550821.
Here is the latest available information:
The next update is scheduled for Friday, November 13, 2026, at 5:30 AM (GMT+7).
If the above response helps answer your question, remember to "Accept Answer" so that others in the community facing similar issues can easily find the solution. Your contribution is highly appreciated.
hth
Marcin