I have setup my Email account and Calender with Thundebird. Everything works fine; I can send/receive emails and view calendar events. However, i am not able to Accept incoming invites on my outlook calendar. I can view the incoming invites and my event attendance updates when i accept/decline the invite via Outlook Web Client. The problem is that when i try to register attendace to "Accept" inside the Thunderbird app, it does not seem to be registered on my calender. It is stuck on "Tentative" Is there anyone with similar problems or knows any solutions to this?