Their manual says it measures 600VAC so they should change their manual if the unit can’t measure normal North American voltages for Commercial/Industrial which are 480VAC/600VAC
Their Manual Says:
The V terminal can measure up to 600V RMS and is intended for
traditional AC and DC voltage measurements.
DC Range AC Range Resolution Noise Floor Accuracy (%+counts)
600 V 600 V 275 µV 9 mV 0.5 + 20