I haven’t received any emails since last night

For a single user in Classic Outlook for Windows, use this order to isolate whether the problem is the mailbox, Outlook, or connectivity:

1. Check whether Outlook is offline.
   • In Classic Outlook, look at the bottom of the window for Working Offline.
   • If it appears, go to Send/Receive and select Work Offline to turn it off.
2. Verify internet access.
   • Open a browser and confirm normal web access.
   • If websites do not load, fix the network connection first.
3. Check whether the mailbox is receiving mail in Outlook on the web.
   • Sign in to Outlook on the web for the same Microsoft 365 account.
   • If new mail appears there but not in Classic Outlook, the issue is likely the Outlook app or profile on the computer.
4. Run Microsoft Support and Recovery Assistant.
   • For a single affected Microsoft 365 business user, Microsoft recommends downloading and running Support and Recovery Assistant on the affected PC to detect Outlook profile, account, and configuration issues.
   • This is not available for new Outlook for Windows, but it applies to Classic Outlook.
5. Check account settings in Classic Outlook.
   • Compare the account settings with the correct POP/IMAP server settings if that account type is being used.
   • If the password was changed recently with the email provider or admin, update the stored password in Outlook.
6. If mail is missing only in Outlook and not on the web, use Outlook troubleshooters.
   • Microsoft provides Classic Outlook troubleshooters for send/receive issues.
7. If Outlook on the web is also not receiving mail, involve the Microsoft 365 admin.
   • Admins can use Microsoft 365 email delivery troubleshooting tools to determine whether the issue is mail flow, spam filtering, service health, or something external.

If the issue started suddenly last night and affects only one mailbox, the fastest end-to-end path is:

• confirm Outlook is not in Working Offline mode,
• confirm internet access,
• check the same mailbox in Outlook on the web,
• if web works but Outlook does not, run Support and Recovery Assistant,
• if web also does not receive mail, have the Microsoft 365 admin use the email delivery troubleshooting tools.

• Troubleshoot Outlook email setup | Microsoft Support
• Find and fix email delivery issues as a Microsoft 365 for business admin
• Issues sending and receiving email | Microsoft Support
• Find and fix email delivery issues as a Microsoft 365 for business admin