Your Me2 has a number of protections built in to prevent anything nasty or dangerous happening. These errors may present as popups from within MatterControl, text on an LCD screen, or within the terminal window of any connected network device.
"Error:Heating failed, system stopped!" occurs the the printer printer is sent a command to heat, and the temperature has not changed within 30s.
Common causes are the power supply is not connected, or the main power to the printer is turned off.
Additional causes may be that one of the red heater wires has come loose from the main board accessible from underneath the printer.