If the gas supply looks fine, the problem could be the igniter inside the oven. If your oven's igniter doesn't glow hot ...

Gas stoves sometimes refuse to light but don't worry, there are several fixes you can try before calling for repairs.

Turn off the power to the oven (switch the breaker to “Off”) before performing this fix. Clean the igniter on a gas stove. If the stove’s burners come on but the oven is not heating ...