Q: Unable to sync calendar with Office 365

There are a number of threads relating to this and it would be useful if Apple would pay some attention to this issue and do something about it!!!

I have 3 Exchange Accounts set up on my MacBook, running OSX El Capitan V 10.11.4.

All 3 Accounts are linked to Office 365.

Mail works perfectly on all 3 accounts. Calendar has stopped syncing on 2 accounts, however one account still syncs ok.

I get the error triangle on the other 2 accounts and the message "Calendar can’t refresh events in the calendar “Calendar”."

I have tried every option suggested on the other threads. Deleted Exchange accounts, killed calendar agent and cleared cache files, removed from recycle bin. I have even tried editing the server pathname. None of this works. As soon as the calendars rebuild, I am left with one working calendar and 2 which wont sync.

I also administer our Office 365 platform and there is no difference whatsoever in these account types.

Any other suggestions would be helpful, this is really frustrating as it worked perfectly well until recently.