Analysis:external system insulation Resistance  is too low
Solution: 
1. Check the wiring situation of DC side and solar panel, such as the existence of poor contact, cable damage and other phenomena; (can judge it by measuring the positive and negative voltage to the ground);
2. Check if inverter/ wire/ solar panel be located in a wet environment.
3. When In a dry environment, to restart inverter(disconnect DC&AC switch, wait for 5 mins, then turn it on), observe if it can return to normal running.