The DC input from the PV strings is connected with reversed polarity.
CauseThe plus and minus conductors of a PV string are swapped at the inverter's DC input, so the inverter sees reverse polarity.
Recommended fixCheck the PV input polarity.
Source:sun-70k-g03-sun-75k-g03-sun-80k-g03-sun-90k-g03-sun-100k-g03-sun-110k-g03-manual.pdf· page 60sun-120k-g01p3-eu-am8-manual.pdf· page 60sun-60k-g01p3-eu-am8-lv-sun-70k-g01p3-eu-am8-lv-sun-75k-g01p3-eu-am8-lv-manual.pdf· page 60sun-60k-g03-sun-70k-g03sun-75k-g03sun-80k-g03-sun-70k-g03-sun-75k-g03-sun-80k-g03-manual.pdf· page 60