Outlook 365 not sending and receiving

Hello Melissa Ford, 

I understand how disruptive it can be when Outlook stops sending and receiving emails. To help me provide the most accurate solution, could you please clarify which version of Outlook you are currently using? (For example, Outlook for Windows, the New Outlook app, Outlook Classic, or Outlook on the web). 

In the meantime, please follow these steps to isolate the issue: 

1. Test via Outlook on the Web 

Go to outlook.live.com 

• If you can send/receive on the web: The issue is likely with your desktop application or local settings. 
• If you cannot send/receive on the web: Please look for any Non-Delivery Reports (NDR) or bounce-back messages in your Inbox or Drafts. If you see any, please share the specific error code or message with me.

2. Repair the Microsoft 365 App (Windows) 

If the web version works correctly, the issue is likely within the Windows application. You can perform a Quick Repair to fix common configuration errors: 

1. Close Outlook and all other Office applications. 
2. Go to Windows Settings > Apps > Installed Apps. 
3. Scroll down to find Microsoft 365 (or Office), click the three dots (...), and select Modify. 
4. Choose Quick Repair and follow the prompts. 

Please let me know if these steps get you back into your account. If you encounter a specific error code along the way, you can share it here so I can look into the next set of solutions for you.