Happens to ours all the time. This is first camper that has been chronic issue. On this stove, if any of the wires leading to the burner are touching metal they ground out and don't spark. I have to continually re route the wires to stay away from each other and not be resting on any of the pipes. You can test by holding the wire up and away from any metal and spin the knob. There will be spark. Then hold the wire down onto the base or pipe and the spark will go away. At least then you know igniter and everything is working
It's a pain.