Electrical Questions? Ask an Electrician Online.
Hi, I'm Mike G and I'll be assisting you. Check the breaker for 240V. Let me know what you get.
The next place to check is the junction box where they are powered. Be careful, you may have a bad connection and an exposed live wire.
You need to test the connections. If you have heating element not working you may have lost one leg of the 240V. Your microwave is 120V and will still work because it is on the good leg and the neutral is good also.