Problem with Champion generator

I bought a new champion 2000 watt inverter generator a couple of weeks ago and it worked great these past two weekends. I went out earlier to winterize my TT so I fired it up and plugged in my trailer. Everything ran fine for a couple of minutes and the generator shut off all of a sudden. I fired it back up and it ran for a few seconds and shut off again. I unplugged it and hooked up my old generator to finish winterizing and all of a sudden the trailer lights went dim and the carbon monoxide detector showed a fault by flashing red and green. I shut everything down and the detector reset itself. I fired up my old generator again and everything worked normally. I finished winterizing my trailer it the brand new Champion gennie still won’t start. I’ve checked, gas, oil and pulled the spark plug to make sure it isn’t fouled. I’m at a loss now. Is there something else I should check before I call Champion and if I have to call, how is their customer service?