Fiat 500 Automatic does not turn up when starting

Hello, I recently bought a Fiat 500 automatic, built in 2019. The car does not turn up when starting up and stays in 1 gear, manual switching is not possible. If I turn the car off and on again it works again and the car switches without problems. The problem only occurs when the car is standing for a few hours. I was already in different workshops and no one can help me. Mistakes have been read out, apparently there are no. White long Sam really not further, depending on where I stand it can also become a real problem if I have to stop and the car has to restart. ???