To get a stable output frequency, use film capacitors (not polarised). Ceramic capacitors are not good for timing, very unstable, the numbers in your screen shot (which you should simply have posted as text) show it's drifting. Polyester film type is normally good enough.
It it doesn't react.to the pot I suspect your wiring is wrong there. Take it out, measure the resistance with your multimeter, see if it behaves the way you expect.