I cant invite my friends to my zombies lobby

1
Hello, i had this problem when i try to invite my friends to the zombies lobby that make it impossible to join, i already add my friends in here and when i invite them to my private lobby they get the invitation, they accept it and then when it shows ''entering the game'' never enters to the lobby, that loading screen just stay there, and then it happends that its an infinite loading or they get the error ''No Available sessions were found. Please try your search again'' and their game resets to the main menu, my friends try to make the lobby and invite me but the same error keeps happening and we dont know what to do, we cant play zombies, i need help to solve this isssue.
cron