DIAGNOSIS A failed power cycle or a firmware hang. The blinking LED indicates the main board is stuck in a boot loop.
FIX Perform a hard reset. Unplug the monitor's power cable from the wall. Unplug all other cables from the monitor (DisplayPort, HDMI, USB). Hold down the monitor's physical joystick button for 30 seconds while it is unplugged. Then, plug only the power cable back in. Press the joystick to turn it on.
IF THAT DIDN'T WORK Try a different power outlet and use only the original Samsung power cable. If it still blinks, the internal power supply board may have failed. This requires professional repair.
HEADS UP Never attempt to open the monitor casing. High-voltage capacitors inside the power supply hold a charge long after unplugging. This is a lethal shock hazard.