Outlook 2010 Stops Receiving Exchange Email
Posted by Russell Wright on April 15, 2015
If you have Outlook hooked up to an Exchange mail box (Office 365 in this case) and mail stops dropping into your inbox, try this.
Right-click on the offending Inbox and click Properties…
Under the General tab, click Clear Offline Items. This will empty the cache. In a scary fashion, all your inbox mail will disappear and (should) will re-sync with Exchange and re-populate.
Hopefully this will clear up your issue. It did mine.