Do not get meeting invites in my inbox.

I have a client the is not getting meeting invites on his outlook inbox. I know there are forums on this but none are mac specific and I am not finding an answer. He does not have any delegates. I set his Arranged by to default. I have turned off show in groups. He is getting the request on his iPhone.  Just not in out look. Is there any other mac changes that i can do to correct this? I have added his account to another computer and he does not see them there either. I'm at a loss. Can someone help me with this? The setting are just different on the mac.