Intermittent fault code

My first guess is that your DC battery bu bus voltage is too low.

Measure the voltage on the DC inverter input.

The wiring needs to be short and heavy. All connections need to be bolted tight. Do not use jumper cables for a car. The alligator clips just do not cut it for high current, low resistance connections.

Can you tell usa bit more about your set-up? Battery voltage and AH rating. DC input cables. Brand and model of inverter, etc....

Bill