The voltage of the PV1 is too high, check the voltage of the string.
CauseThe open-circuit voltage of the PV1 string is above the inverter's permitted DC input range — typically a string configured with too many modules in series.
Recommended fixPower down the inverter, wait 5 minutes for capacitors to discharge, then restart. If the fault recurs immediately or repeatedly, record the exact code and contact your installer or the manufacturer's service line.
Source:t-rex-25-50khp3g01-user-guide-en.pdf· page 45