Thanks for getting back to me. Are you all able to play other modes just fine? Quickplay, drop-ins, etc.
Everyone should check their privacy settings on their Xbox. Make sure there is nothing that would prevent them from playing multiplayer.
Also, it's possible this is related to a bugged vanity item. You all would need to be using the same item though. Skates, stick, gloves, hair, etc. I think this is pretty unlikely, but it's not impossible.
You could also try creating a new club. Let me know if that's an option.