DIAGNOSIS The washer isn't registering that the lid is fully closed and latched, so it won't engage the lock or start.
FIX Ensure nothing (like a sock or label) is obstructing the lid strike (the plastic piece the lid presses down on near the front hinge). Firmly press down on the lid center until you hear a distinct click. The light should turn solid.
IF THAT DIDN'T WORK The lid lock switch assembly itself could be faulty. Unplug the washer for one minute, then plug it back in. If the blinking persists with a clear strike area, the switch likely needs replacement.
HEADS UP Never try to force the lid open when the light is blinking or solid. The lock mechanism is engaged for safety during spin. You can manually release it via the emergency cord inside the console or by unplugging the machine for several minutes.