Outlook emails are not syncing on macOS

I have been experiencing several synchronization issues with Outlook for Mac when using my IMAP email account.

My environment:

• macOS 26.6.2
• Outlook for Mac 16.112.3
• Microsoft 365 subscription

First, emails that I delete from my Inbox sometimes reappear several minutes later.

In addition, I have confirmed with my IT support team that incoming emails are successfully delivered to my IMAP mailbox. However, Outlook often fails to synchronize and display those messages. Even when I manually initiate a sync, the missing emails do not appear.

I do not understand why the synchronization is so unreliable. I have already reviewed several online articles and troubleshooting suggestions, but none have resolved the issue.

1.Update Microsoft 365 or Office on macOS:

https://support.microsoft.com/en-us/office/lifecycle/officeinstall/update-m365-office-macos-ios

2.Clear the cache in Outlook for Mac

https://support.microsoft.com/en-us/outlook/clear-the-cache-in-outlook-for-mac

3.Repair Outlook Data Files (.pst and .ost)

https://support.microsoft.com/en-us/outlook/repair-outlook-data-files-pst-and-ost

4.Outlook for Mac – Email Synchronization Troubleshooting

https://learn.microsoft.com/en-us/answers/questions/6003894/outlook-for-mac-legacy-outlook-not-syncing-one-ema

Has anyone experienced similar behavior with Outlook for Mac and IMAP accounts? Any assistance or recommendations would be greatly appreciated.

Thank you very much for your help.