there are two common reason for G15 to blink its LED.
1. Overload. G15 will off its torque when overload. Please release G15 to let it free running without connecting any load to G15 shaft. power off and on G15 to reset the overload error in order to let G15 run normally again.
2. overHeat. power off G15 and let it cool down for few minutes before turning on G15 again.