Seems a bit obvious I know but is there a chance that it's tripping the gfi on the generator. Try multiple receptacles also, sometimes the blades can get worn out in the receptacles if it's a well used gen or pump cord end, possibly making a bad connection on there and not on the wall plug you tried it on. Like was mentioned already too try simply moving the cord around to see if there is a loose connection anywhere. It doesn't seem like an issue of overload, more a connectivity issue. Just my 2cents!