This one has taken me some time to figur out - its a kind of error from consequence of another error as I will try to explain here:
When TB started we where two players putting up defenses against an opponent with just 23 players.
Some time later other teammates woke up and reported that their TB was not done matchmaking yet!
I restarted the ML APP and right away encountered the very same thing: no access to TB, matchmaking not ready (and that was hours after I placed my first defenses).
When matchmaking was done and we all had acces to TB, we had another opponent - not the opponent mentioned above. The defenses I had made where gone.
I restarted the ML apps and a couple of the defenses i had made re-appeared, but most where gone. No problem - I just make them again, I thought. I have tried at least 10 times and everytime the ML apps crashes with a "Something is wrong.." and a Restart button.
I guess the problem is that the monsters I have prepared and used in the first place never got "recalled" - they are still "out there" somewhere either in the twilight zone or on a real Team Battleground on a unknown Team (I know the name of the opponent, though).
So if any of you has the same strange experience or even see my name appear as if I where on your team (besides my own teammates, that is!!!), then please write here!