NPN Transistor not working
Suspicion : because we don't know what this LED is. (Datasheet for it might be useful).

If it is actually a network of LEDs - say 4 white LEDs (Vf=3V each) then it needs 12V to start turning on, and R1 to limit current to 12mA (6V/470R).

Then the voltage divider ensures the voltage cannot rise above 12V, but any attempt to turn on Q1 draws current from the voltage divider, lowering its voltage below 12V, and guaranteeing the LED will not illuminate.

If this is the case, then it is safe to increase R2,R3 or omit them altogether. Then, when the transistor is off, both ends of the LED are at 18V so there is no voltage across it, and it is off.
When the transistor is on, there will be some small voltage across it (0.2V if it is in saturation), 12V across the LED, and 5.8V across R1 limiting the current to around 12mA.