Default [Q] Pantech discover att to straight talk sim card not provisioned mm 2

I've got an unlocked art Pantech discover, and I'm trying to make it a straight talk. I am trying to make the correct similar card activated. The att micro sim is saying sim card not provisioned mm #2. I haven't activated any cards yet. From what I hear the problem will go away when I call to activate the card. I want to make sure though. If anyone can help I would appreciate it. I have already lost money trying to figure out what phone I want. I don't want to mess up again.