There are a few steps you can try to resolve this issue:
Re-create the Outlook profile from scratch. Go to "Control Panel" > "Mail" > "Show Profiles" to create a new profile and add your email account to it.
Repair Outlook Data Files. Corruption of the Outlook data file (.pst or .ost) can also cause synchronization issues. You can try running the Inbox Repair tool (Scanpst.exe) to check for and repair any corruption in your data file.
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Start Outlook in safe mode and disable add-ins. Sometimes add-ins can conflict with Outlook. Starting Outlook in safe mode, which starts Outlook without add-ins loaded, can tell you if an add-in is the problem. If Outlook works fine in safe mode, then the problem is likely with one of your add-ins.
To run Outlook in safe mode, right-click the Start button, and click Run. Then type Outlook.exe /safe, and click OK.
To disable add-ins, go to "File" > "Options" > "Add-ins" and select "COM Add-ins" from the Manage dropdown. Then click "Go" and uncheck any add-ins that are causing issues.
Temporarily disable antivirus software or firewall. Some antivirus software or firewall can interfere with the functioning of Outlook. Temporarily disabling your antivirus software can help you determine if it's the cause of the problem. Be sure to enable them again in time.
Repair Outlook. Right-click the Start button
(lower-left corner), and select Apps and Features on the pop-up menu. Select the Microsoft Office product you want to repair, and select Modify.-
Completely uninstall Office using this tool: About the Microsoft Support and Recovery Assistant - Microsoft Support. After that, select the steps for the version of Office you want to install or reinstall.
Microsoft 365 | Office 2021 | Office 2019 | Office 2016 | Office 2013 | Office 2010 | Office 2007
This tool can also can help diagnose and resolve various issues with Outlook.