Analysis: Inverter internal FAN is faulty
Solution: 
1. Inspect if the FAN cover plate is deformed
2. Observe if the FAN can normally running( judge it by hearing the running sound or use a hand to feel the wind status)
3. Disconnect the both of AC and DC side switch, after 5 minutes, to check if the FAN connection wire is loose
4. Replace the faulty fan, and observe if inverter can return to normal