My Outlook 365 is not receiving emails

Try these steps in order to restore sending and receiving in Outlook 365:

1. Check storage limits
   If Microsoft cloud storage is full, email cannot be sent or received.
   • Open the mailbox storage page from Outlook (for example via the storage warning link) and review usage.
   • Delete or archive items as needed, then empty Deleted Items.
   • See the notes under New Outlook in I can't send or receive messages in Outlook about storage.
2. Run the Outlook troubleshooters/diagnostics
   • For classic Outlook for Windows, go to the Classic Outlook troubleshooters page and run the appropriate troubleshooter for send/receive issues.
   • For Outlook connected to Microsoft 365/Exchange Online, an admin can run Run Tests: Outlook User Connectivity from the Microsoft 365 diagnostics described in Fix Outlook connection problems for Microsoft 365 account.
3. Update Outlook and Windows
   Out-of-date software can break mail flow.
   • Run Windows Update to install the latest updates for Windows and Microsoft 365 apps.
   • Restart the device and reopen Outlook, then test sending/receiving.
4. Check Outlook’s connection status
   • Make sure the device has Internet access (open a few websites to confirm).
   • Ensure Outlook is not set to Work Offline.
   • If using Outlook for Mac, verify Work Offline is not checked on the Outlook menu.
5. Check account configuration (POP/IMAP/SMTP)
   If using POP/IMAP:
   • Confirm incoming and outgoing server settings with the email provider.
   • For Outlook for Mac, if messages will not send, enable SMTP authentication: Tools → Accounts → select account → under Outgoing server choose More Options and configure authentication and credentials.
6. Repair profile and connection issues
   Common issues include corrupted profiles or connection problems to Exchange/Microsoft 365:
   • Use the Support and Recovery Assistant for Microsoft 365 from Fix Outlook connection problems for Microsoft 365 account to automatically detect and fix common connectivity problems.
   • If issues persist, create a new Outlook profile and reconnect the account.
7. Check for service-wide issues (admins)
   If multiple users are affected:
   • An admin should check Microsoft 365 Service health status for Exchange Online to see if there is an ongoing incident.
8. If still not working
   • Use the Outlook troubleshooters again for the specific scenario from Issues sending and receiving email.
   • If none of the tools resolve the problem, contact Microsoft support from the link in that article.

References:

• Issues sending and receiving email
• I can't send or receive messages in Outlook
• Fix Outlook connection problems for Microsoft 365 account
• I can't send or receive messages with Outlook for Mac