Using older versions of Outlook for Mac in business environments
I had this issue too. After 30 minutes on the phone to Microsoft help desk being passed around I got the line that it was caused by the version of exchange server that the effected account was hosted on. Given the other posts in this conversation I am really skeptical this is the cause because the individual I spoke to was unable to tell me, which version would work apart from the latest version of Exchange. I have now uninstalled Outlook 365 and gone back to Outlook 2011. My concern is that this issue will persist when the Office 2015 for Mac comes out.