Hi I can not join the league lobbies. I could when the update happened but not now.
I got an error on the servers not being available twice yesterday. I backed out to FM6 main menu and tried again. That got me in both times. If that does not work. Test your multiplayer connection under settings and try the link below if there is an issue.
https://support.xbox.com/en-US/xbox-one/networking/multiplayer-connection-error-solution