The reason for this NAT status is in most cases related to Xbox Ones bad IPv6 implementation.
So if you have a fritzbox or something else with activated Teredo-Protocol, just deactivate this option and your NAT status should change.
UPnP should also be activated, but in most cases, the issue is related to the activated Teredo-Protocol.
English
-
How do I deactivate teredo protocol?
-
I.....wow...