It might be account related, But I have not found a fix. So in your case try logging into a different Xbox account (Not sure if it will allow you to play so, maybe might need xbox pass on new account OR use a friends account that has the simulator already if you guys trust each other) on the MS store and Xbox app. Then to make sure you log out of MSFS go and press the Windows start key, then type “Credential Manager”. After that open go and Click “Windows Credentials” and find the one that has : ‘Xbl_Ticket’ at the front of it. Remove that and your MSFS should be logged out of you Xbox.