It's almost certainly the igniter. I replaced mine recently, paid $85 at a local store for it, then found out I could have got it on ******** for about $8 including shipping. I had to take the back of the oven off, just lots of screws, no biggy, replacing it was easy.
I'm sure this is almost always the problem. Unfortunately, for me, this didn't do it. I do know the old unit was bad: I checked it out, and the new one works But the oven still doesn't light.
Not sure what the next step is for me.