The story of CrossfireX is a sad one. At one point, it seemed like the Xbox Series X and Xbox Series S exclusive shooter was going to be a major hit on the platform, but a poor launch saw the game crowned the worst Xbox release of 2022 (according to Metacritic), and that was followed up by an apparently rapid loss of players following its release.
Some impressive updates weren't enough to salvage CrossfireX, and it was announced back in February that the game's servers would be closing on May 18th, 2023. That's the very last time you'll ever be able to play CrossfireX on an Xbox console, as the servers are required even if you want to experience the single-player campaigns.