Gas ignitor Issue

The ignitor was not working so i replaced it. The burner will now light and work normally. Here is the catch. When I replace the the flame defector that goes over the top of the burner the ignitor glows, gas will fill the burner but now the burner will not ignite…If i remove the flame deflector and turn on the oven it will work. This is very strange as you would think that the deflector would contain the gas to the area near the ignitor and ignite easily. Please help as this is driving me crazy…Thank you