According to the manual, that's a fault code where one of the Xantrex inputs is bad, specifically the neutral.
The neutral is the white wire.
I'd start be verifying that your circuit breaker box is electrically correct. While on shorepower, measure with a voltmeter and you should have 120Vac from line 1 (black) to neutral (white), and from line 1 to bare wire ground. Should also have 120vac from line 2 (red) to neutral, and from line 2 to bare wire ground. Then you should have 240vac from line 1 to line 2. Neutral (white) to bare wire ground, should be 0.
If those aren't good, you need to back up to the transfer switch, an EMS if you have one, shorepower cable, and/or shorepower post.
If however your circuit breaker box is electrically correct, then you need to check the wires from the breaker box to the Xantrex, to see where you are loosing the neutral.'
If you're not comfortable working around electricity, hire someone to trouble shoot this.
DaveB, Raleigh, NC
2015 Tiffin RED 33AA
2014 Honda CRV