CRM Calendar Sync Not Working

CRM Calendar Sync Not Working

I can't get any meetings where I am a participant to sync with either Bookings or Office 365. It syncs fine when I am the host, but as a participant, it just ignores the event.  I have clients booking meetings when agents are in training or OOO or any of the other myriad of meetings one can have in CRM. 

Sync to either service also ignores any "Mark As Unavailable" events and Calls.  How do I get it to work right?

Thanks in advance,
Mats