If the board is truly restarting, IE, you get the splash screen which would be what you see when you first turn it on, or if you go away and come back to the screen looking like it hasn’t printed (it would say something along the lines of “printer ready” rather than “done” or something like that) Then it could be that your power supply doesn’t have enough wattage. Do try the other suggestions before getting a new supply. It could be a problem with Cura or with that STL.
If you have a multi meter, you can check to make sure that your supply has enough power. Plug everything in to your printer and turn it on. Read the voltage off of the power supply. If the voltage is around 11V or lower, then you have a problem. If it is 12V or higher than you should be good.
Again, try to fix it in Cura first before the power supply, that will save you at least $30 if you’re in the US. Not sure what they cost in Euro.