If your oven is not heating, the issue could be caused by a faulty heating element, a broken thermostat, a defective igniter (for gas ovens), or a malfunctioning control board. For electric ovens, the bake or broil element may have burned out. For gas ovens, the igniter may be weak and not lighting the burner properly. If your oven isn’t heating, it’s best to schedule a professional oven repair service to diagnose and fix the issue.