Please check that you set the right clamp sensor type at the SET UP range (Setting 04). It should be same as the clamp sensors which you use for measurement.
This SET UP range (item No.04) is to set the type of clamp sensors you will use but not to set the current range.
For example: (M-8124:1000A, M-8125:500A, M-8126:200A, M-8127:100A, M-8128:50A)
Be sure to use the same type of sensor when you use more than one sensor. It is possible to connect maximum 3 clamp sensors at one measurement, however, it is possible to use one type of clamp sensor.
Be sure that the test leads are connected correctly to the voltage input terminals. At the single-phase 3-wire and three-phase 3-wire measurement, connect the test leads at VN (blue), V1(red), V2(green) at the voltage input terminals. Connect the lead at V3(black) terminal only at the three-phase 4 wire measurement.