Outlook Not Syncing

How to Fix Outlook Sync and Connection Errors

If your Outlook is not syncing, emails are stuck in the Outbox, or you are receiving server connection errors, follow these troubleshooting steps to resolve the issue:

Check "Work Offline" Mode: Go to the Send / Receive tab. Ensure that the Work Offline button is not selected. If it is, click it to go back online.
Clear the Outbox: Sometimes a large attachment gets stuck. Go to the Outbox folder, delete or move any pending emails to Drafts, and try sending them again one by one.
Manual Sync: Click on the Send / Receive tab and select Update Folder or Send/Receive All Folders to force a sync.
Repair Account Settings: Navigate to File > Account Settings > Account Settings. Select your email account and click Repair. Follow the prompts and restart Outlook.
Disable Add-ins: Go to File > Options > Add-ins. At the bottom, select COM Add-ins and click Go. Uncheck all active add-ins and restart Outlook to see if the conflict is resolved.
Verify Server Settings: Double-check your IMAP/POP and SMTP settings. If you use Gmail or Yahoo, ensure you are using an App Password if Two-Factor Authentication is enabled.

You might be better served by posting this question in the Outlook Q&A Forum:

https://learn.microsoft.com/en-us/answers/tags/778/office-outlook

This presents your question to a much larger audience and gets you access to the Outlook Subject Matter Support Specialist who monitor that forum.

Please answer the following questions to I can understand your issue better

1.  Are you using classic outlook or new outlook?
2. if you are using classic outlook on the bottom right side next to the zoom you can see the sync status of your outlook , it could say all folders are syncing or all folders are up to date. Please share what you see.