Xbox One error code 0x803f800b is an error that usually occurs when the user is having problems with the game as it starts up then crashes.
Some of the solutions to this error include:
Please see our in-depth walk-through solutions below.
If you have subscribed recently but the error persists, please turn off then unplug for at least three minutes. Turn on your Xbox One again and check if you can play. If not, call customer support.
Activate Xbox Gold+ Membership
Xbox one error code 0x803f800b may also be caused by trying to access a Gold+ Membership, which requires a subscription. Please subscribe Xbox Gold+ Membership.
Xbox One error code 0x803f800b appear when your subscription ended. However, if your subscription is active the problem might be cache. To fix this hard reboot your console by hold Xbox power button on the console for 10 seconds until it shut down then unplug it for at least 30 seconds for the power cycle.