cannot send and receive email in my outlook

Check Microsoft 365 service health first because a sudden send-and-receive failure beginning this morning may affect the service rather than your Outlook installation.

1. Check for a Microsoft 365 incident

• Microsoft 365 administrator: Open Microsoft 365 admin center → Health → Service health → Exchange Online. Review Active issues Microsoft is working on, including the user impact and latest update. Administrators with the Service Support or Helpdesk Administrator role can also view this page.^1^
• Non-administrator: Check the public Microsoft 365 service-status page.^2^
• If Exchange Online is degraded, monitor the incident rather than repairing Outlook. Microsoft handles restoration, and mail delivery may be delayed while the incident remains active.^3^

2. Determine whether the mailbox or Classic Outlook is affected

Open Outlook on the web and test sending and receiving there.

• Webmail also fails: This points away from the desktop application. If no service incident is posted, ask your Microsoft 365 administrator to run Microsoft 365 admin center → Diag: Troubleshoot Email Delivery. The administrator can then use Exchange admin center → Mail flow → Message trace to inspect a specific test message.^3^
• Webmail works: The mailbox is functioning, so continue with the local Classic Outlook checks below.

3. Check Classic Outlook locally

1. Look at Outlook’s bottom status bar.
   • If it says Working Offline, Disconnected, or Trying to connect, select Send/Receive → Work Offline to return online, then select Send/Receive.
2. Check Outbox.
   • Open the oldest stuck message first. Remove or reduce any attachment larger than 20 MB, then resend.
3. Start Outlook without add-ins:
   • Press Windows+R.
   • Enter outlook.exe /safe and press Enter.
   • Test sending a small message to yourself.
4. If Safe Mode works, disable add-ins:
   • Go to File → Options → Add-ins.
   • Beside Manage: COM Add-ins, select Go.
   • Clear all add-ins and restart Outlook normally.
   • Re-enable add-ins individually until the problem returns.

Microsoft identifies offline status, stuck large messages, profile problems, and add-ins as common Classic Outlook causes.^4^

You can also open Microsoft’s Classic Outlook troubleshooters and select the send/receive or connectivity troubleshooter. These troubleshooters apply to Classic Outlook, not New Outlook.^5^

4. Conditional check for POP3 and KB5074109

Only take this action if both conditions below are true:

1. In Outlook, open File → Account Settings → Account Settings and check the Type column. It must show POP3.
2. Open Windows Settings → Windows Update → Update history and look for KB5074109.

If both apply:

1. Go to Settings → Windows Update → Update history → Uninstall updates.
2. Select KB5074109 and choose Uninstall.
3. Restart Windows and test Outlook.^6^

Removing a Windows update can temporarily reduce security. On a business-managed computer, obtain IT approval before uninstalling it.

References

1. How to check Microsoft 365 service health
2. Microsoft service health status
3. Find and fix email delivery issues as a Microsoft 365 for business admin
4. [Classic Outlook](https://support.microsoft.com/outlook/i-can-t-send-or-receive-messages-in-outlook#make-sure-you're-connected-to-the-internet)
5. Issues sending and receiving email | Microsoft Support
6. my classic outlook keep freezing and i cannot send emails. - Microsoft Q&A