Know nothing about that specific generator. I’m assuming you also have a 220V outlet. I would start by checking the 220V outlet to confirm you have 220V between the two hot legs and 110 between each hot and the neutral. If you’ve got a dead hot leg there also that would be consistent with one of your 110’s being dead and would indicate potential serious problems with the generator putting out power on only one side. If the 220 is working correctly, then you know the generator output is correct and more likely there’s an issue specific to that 110 outlet.
I’m aware that doesn’t solve your problem. May give you a place to start looking.