Gas dryer not heating up

I have a gas dryer Estate and it is not heating up I have replaced the dryer igniter unit thing and it still does not heat up? What can I do to fix this?

if the ignitor does not come on, it come be 1 of 2 things. the thermal fuse in the back. it is white in color, and has 2 wires coming to it, or the flame sensor, mounted on the side of the flame tube. tom applianceeducator.com or

Thank you for your help, I have ordered both parts to be on the safe side so we will have to see if it works after I get them. I will be in touch. Thank you!

Good Luck. Tom ApplianceEducator.com