Why do my Enphase micros report 'AC Voltage Out Of Range' on sunny afternoons?

Short answer

Enphase 'AC Voltage Out Of Range' means the microinverters saw grid voltage outside their permitted range and stopped exporting until it recovered. Occasional events are normal. If the whole system trips often on sunny afternoons, local voltage may be high or cabling undersized; your installer can measure voltage rise and, if needed, raise it with your network operator.