Why did red light come on saying stop engine battery, alternator

It's the aux battery... It probably needs a charge, driving the car for a bit and then maybe restarting should ale care of it... Either the car was parked for a while and the batter just needed a light charge to get going or you probably need to get it checked out by a Benz repair specialist... For me driving it around for about 15 min and the. Restarting helped out just fine...