Accepting Gmail Invitations With eM

When I receive an event invitation and I click accept in eM it says I have sent a status response to the organizer, but the event does not appear on my calendar. 

It is as if Google Calendar did not receive the alert to add the event.  I have to use the web access to my gmail to accept the invitation if I want the event to appear on my google calendar. 

Is this a settings issue in eM?

Thanks for your help.