Do you have any of the automatic processing options configured? What kind of mailbox is this? Have you checked for rules? You can enable auditing on the mailbox and check what happens upon a new invite arriving.
I have encountered couple of cases so far and haven't found any fix. Used MAPI Editor , used outlook command switches but no positive outcome. Any help on this case is greatly appreciated.
@Melissa936@Marvin Oco did you previously associate your domain with Google Business and then move the domain to O365? We have a similar issue, but since the original user had her calendar invitations set up with a delegate, the delegate still gets the invitations.
