The only thing I can imagine doing that might've caused the issue is starting up the system incorrectly. I believe one time I turned on all four batteries and then closed the breaker that sits between the batteries and the inverter. I know you're supposed to close that breaker first and then turn on the batteries.If the error code persists after a full shut down then you have a real issue in my opinion. I’ve seen a video on YouTube where someone had that problem. SS warrantied his unit I believe. You didn’t exceed your voltage limit?