@dljrwj do you have an active Xbox Live Gold membership? You need Xbox Live Gold access in order to play online multiplayer games on your Xbox. If you have an active Gold profile, I recommend to get in contact with one of our Game Advisor for a further account check: http://help.ea.com/en/contact-us/new/?product=plants-vs-zombies-garden-warfare
Our Game Advisor can check your account and can investigate what might blocking you from playing but will need some of your private details for the verification process.
Cheers
Basti
