Kenmore Gas Dryer won't stay lit

Hello,
I’m having problems with a kenmore natural gas dryer. When you first start the dryer it will ignite and burn for about a minute. With the back cover removed I can see the ignitor lite and it will not produce a flame again. If you wait 15 minutes it will do the same thing. I’ve disconnected the vent hose and just let it blow out. I found a troubleshooting guide and checked the resistance on the ignitor and flame sensor and also the coils. Everything seemed to check good. I removed the drum and started the dryer and it would cycle and ignite the flame every 20 to 30 seconds. I reassembled and tried it and it did the same, flame burn for about a minute and the ignitor would glow and not ignite a flame. Think it could be the coils?
Thanks in advance,
Randy

I posted on here a week or so back hoping for some help in troubleshooting the problem with my dryer. I’ll try again on getting a reply.
Randy