The 74HC14 and the 4066 must both use THE SAME supply voltage and ground.
Point A on your schematic is the output of the 74HC14 that swings almost from the supply voltage to almost ground which is plenty to turn on and off the 4066.
If the light is very bright (sunlight or a laser beam) then the resistance of the photo-resistor is too low for the output of the 74HC14 to drive and the voltage swing will be low or the oscillator will stop.
Add a 1k resistor in series with the photo-resistor to prevent it.