we apologize that you are having this issue with the inverter. Usually when this happens, it means there is a problem with the wiring.
Do you have a wiring diagram by any chance?
On the first picture you posted, it has two red cables going to L1 and L2. It's a little hard to tell which is which without any labels on the wires but make sure the AC input is also grounded to the inverter.
Also, where do you have your neutral ground bond?