Xbox one teredo ip is not found?

I have already released all ports and disabled the Teredo filter (have a Frotzbox 7490). Nevertheless, I'm not able to join or play in parties (have 20 mbits up- / download).

I do not know what to do any longer you can help me there (live in a dorm therefore have no contact to the Internet provider)

I have released my Xbox as Exposed Host. This has solved the problem.