furnaces and water heaters will attempt to light 3 times. You hear the 'clicking' cycle 3 times that means all is well with controls, but no ignition, so it goes into lockout.
If you are certain you have propane -a stove high burner test, - then go outside and listen to the light attempt. Look at the exhaust. These will tell you if you have arestricted air flow, such as an insect nest in the burner tube or an over air flow which blows out the flame.
Altitude is a factor in either case, for low altitude restricting the air intake with a bit of tape( fingers over one or another ) intake until the burner lights smoothly with no whoose 'jet ' sound.
At high altitude, it could be starving , enough air to activate controls yet not enough for settled combustion. You would hear a soft attempt to light perhaps see soot. Another sign of restricted burner tube or too high propane pressure.
Consult a professional.
