Hello, thank you for requesting me, and for the confidence in my abilities!
The single most common cause of this issue is that the set is nolonger producing electricity.
The first thing you need to do, though, is to check your oillevel and make sure it is full.
Low oil pressure will also shut the set down.
If the oil is good, remove the control panel from the front of the genset.
Set your meter to ACV.
Connect the black lead to a good ground.
Connect the red lead to the back of the circuit breaker (either one), on the terminal farthest away from you.
Press and hold the start button for 6 - 8 seconds, and note the voltage.
How much voltage is there?