Sorry for posting an not getting back in timely manner. Too much going on all over the place.
The generator / AC tandem has worked in the past.
Not sure what you mean by the ATS or ATF ( I assume either someone had a typo or the same thing has more than one name)
As for "what do I mean everything resets", it's hard to say. Everything on the DC side seems fine at the time. The radio keeps playing. Lights stay on.
Everything on the AC side shuts off. And if I watch the control panel, it only briefly goes dark, then starts up like I first turn on the generator.
Sounds like my next step is to reproduce the problem and read the volts coming off the generator.
It's a 5.5kW Onan