You need to click on this option to unselect it and make the application work in online mode. If this Work Offline option is selected, there is a check mark against it. You can check whether Work Online mode is opted by launching the Outlook for Mac application and going to Outlook>Work Offline.

Sometimes users forget to undo the Work Offline mode for its Outlook for Mac application and this could be the silly reason behind the synchronization problem between the application and the Exchange Server.

Utilizing Inbuilt Microsoft Database Utility.

Re-building Outlook for Mac Database File.

We have got a list of the manual solutions which users can follow and perform to resolve the synchronization problem between Outlook for Mac application and the Exchange Server. Native Fixes for Outlook for Mac Not Syncing with Exchange Server. The best option here is to troubleshoot each aspect and work accordingly. It can be via bad Internet connectivity, incorrect LAN settings, incorrect Encryption settings, failed Server connectivity, Files corruption, Cache corruption, or more. One cannot confirm the exact cause behind it without troubleshooting. But unfortunately sometimes users have to experience an unwanted situation where their Outlook for Mac is not syncing with Exchange Server. The Exchange data can be accessed in the email client application and the data is updated with the synchronization processes. Outlook for Mac is a Mac environment email client which allows configuring the Exchange Server account within it.

(other common Outlook for Mac errors and their solutions) But due to some bad settings or connectivity issue, the result is somewhat else – the synchronization error. Synchronization of an account to the client application works efficiently when the data updated regularly as soon as it is processed.

Mac mail exchange settings