Outlook 2016 connected to exchange but not updating
Emptying the cache replaces the contents of the folder with the latest items from the Exchange server.Before emptying the cache, you may want to ensure that your Outlook information is backed up.Ask your Exchange account administrator which proxy server you should use to connect to the Exchange server.
Additionally, if you connect to your Exchange account over the web, use a web browser to see whether you can access Internet sites.
The email account that outlook is logged into appears to sync ok without needing to click Update Folders, it's only "shared" mailboxes.
Is there a setting that needs changing or is this how cached mode works. Please refer to this KB article for more information: https://support.microsoft.com/kb/3115602 There are a couple of different options you can take to resolve it depending on what works best for you.
If you've successfully connected to the account before, try to connect to it from another Exchange application, such as Outlook on the web.
Solution: Contact your Microsoft Exchange account administrator.