If you’re having trouble playing in a tournament, try the following solutions:
The tournament is full. Try registering for another tournament.
You didn’t check in. If you registered for a tournament, you may need to confirm that you’re ready to play. If you missed check-in, you’ll be removed from the tournament.
The game isn’t installed, or you don’t own it. You can install games from Home > My games & apps. Also, make sure that the game has the latest updates installed (launching the game will ensure that you have the latest version). If the title isn’t in your Games or Ready to install list, you’ll need to get it from the Microsoft Store.
A temporary connection problem may be preventing you from using Arena on Xbox Live. Wait a bit and try again.
You don’t have Xbox Live Gold or Xbox Game Pass Ultimate. To play games that support Arena on Xbox Live, either you or someone on the console you’re using must have an Xbox Live Gold or Xbox Game Pass Ultimate subscription. (You don’t need Xbox Live Gold or Xbox Game Pass Ultimate to register for tournaments.)
You’re suspended or banned from Xbox Live. If you haven’t received a notification, check your enforcement history.