Why the same GPIO pin is not working anymore?

Question

I was working with a very simple code:

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
GPIO.setup(24,GPIO.OUT)
GPIO.output(24,GPIO.HIGH)

But after running one time when I am running the code next time the Thonny IDE is showing me

RuntimeWarning: This channel is already in use, continuing anyway.  Use GPIO.setwarnings(False) to disable warnings.
  GPIO.setup(24,GPIO.OUT)

Why is this happening?

Answer 1

The GPIO is still working, it's the software refusing to continue without a warning unless you correct the condition causing the warning.

Either do what the warning message says or add the following line at the (logical) end of your script.

GPIO.cleanup()