2007 smart fortwo car

Hello, i need your insights and help what would be the problem :(

My smart car whose mileage is 55,000 suddenly stopped last night when I was about to enter the roundabout. ( before that i am on 40mph in the dual carriage way and ofcourse i stop for 3 mins to wait for my turn at rounabout)

I’m completely clueless of what happened why the engine stopped and after 10 mins it turned on. I noticed that there’s a squeeky sound when i turned on the electrical in the morning but it will be gone after 2-3 mins.

I went to formula one this morning and they told me that their diagnostic reader can’t read my smart car 🤦🏼‍♀️