E0 code on AC-help!

2 years ago, I bought a Newair 6,800 BTU portable air conditioner/dehumidifier (never used the dehumidifier feature). I store it properly during the off season and have had no issues until tonight. I went into my bedroom to notice it flashing an E0 code. I turned it off and back on and the code appeared again, went away, and the unit started running as usual. After a half hour (give or take) the code came back. I unplugged it this time, waited a few minutes, and the code came back again as soon as I plugged it back in. The instructions state for this code that it indicates “communication errors between main PCB and display PCB” with a remedy of “check the wire harness of the display PCB for damage”. I am not educated whatsoever in hvac or electrical but I’m handy with YouTube and would rather try and figure this out myself and not have to spend money on a technician. Anyone able to walk me through what the heck I’m looking for or doing? Is this just a display issue or is there something more dangerous wrong with my AC?