Outlook 365 not receiving emails

Hi Scott Curry

Thank you for posting your question in the Microsoft Q&A forum.

Based on your description, I understand you're experiencing an issue where emails have not been received in Outlook (both mobile and desktop) since October 4, 2025. 

As a first step, I recommend trying the following quick checks:

Outlook Web Access 

Please log in to Outlook Web App and confirm whether any new emails have arrived since the mentioned time. This will help determine whether the issue is specific to the Outlook applications or affects the mailbox itself. 

Mailbox Storage 

Please verify that your mailbox has not reached its storage limit, as this could prevent new messages from being delivered. 

Go to OWA > Click the Settings gear icon in the top-right corner > a settings panel will open and at the very top of that panel, there is a search box that says "Search all settings" then simply type Storage into that search box. 

If you have admin access (Microsoft 365), you can try advance steps as below: 

• Check service health on Admin Center
• Message trace in Admin Exchange > Mail flow > Message trace 
  • Trace your address from Oct 4 5:55pm onward. 
  • If “Delivered” to your mailbox: it’s a rules/folder/filter issue. 
  • If “Failed/Rejected/Deferred”: open the event and note the SMTP code (e.g., 5.2.2, 5.7.1, 5.4.1/4.4.x). 
• License: Admin center > Users > Active users > your account > Licenses and check again to ensure an Exchange Online license is assigned. 
• Domain/DNS: Admin center > Settings > Domains. Domain should be “Healthy.” 
• Quarantine: Go to Quarantine > Email & collaboration > Review > Quarantine to see if inbound mail is being held. 

If the issue still persists, to assist you more effectively, could you please share additional details about the issue you’re encountering? 

• Are new emails visible in Outlook Web? 
• Have you encountered any error messages or sync warnings? 
• Can you send out?  
• Mail flow rules/connectors: admin.exchange.microsoft.com > Mail flow > Rules/Connectors look for recent changes around Oct 4. 

I hope this information is helpful and I look forward to your response.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.