Smart 451 suddenly doesn’t start anymore

Servus, I have a problem to report, hope for your knowledge and help. And I drove with my smart shopping, when I had done my shopping (knappe 10 min) he suddenly no longer jumps on. So if I plug my key in he shows me everything possible, radio also works. At the battery it can not lie because I have replaced it a month ago. I also can not change gear, shows me constantly N. Changing gear is somehow not in. If I want to start the engine does not do anything at all a noise or anything else, except a short cracking. Can’t be that the car makes palaver after only 10 min standstill. Please for help! Thank you