Cause:
Loose connection in the surge arrestors signal plug or in APP board, defective CAP or Surge arrestor
Resolution:
First, perform LOTO to make sure all energy in the inverter is zero. Checked the cap for sign of leakage or deformity. Check surge arrestor F5-F8 to see if any of them was bad. Check F4 Surge arrestor. If everything is checked out fine, try cycle the inverter AC power. Wait for about two minutes before turned it back on. If the fault does not clear after cycled power, call into the customer call center number 866-519-1470 and select option 3 & 3 to open a new case.