Overtemp protection of a driver? They usually start again after a few seconds, but then the print is messed up already. Next time, just wait and see.
If the whole print stopped, it might be the onboard 5V regulator or the polyfuses ( Atmega/Ramps combo )
If the whole print stopped, it might be the onboard 5V regulator or the polyfuses ( Atmega/Ramps combo )