NLP status frequently coming on ATV320 VFD

Hi,

I have a Schneider VFD - ATV320, 1.5kW for a Horizontal motion in which when it is running it shows nLP intermittently in between. First DBR connected was wrong then we replaced with correct one which resolved braking fault problem.

But this nLP is not going at all and it is other VFDs(used for other motions on same machine) as well.

We checked input power by multi-meter and it is ok i.e. 400V - 3Ph during standstill and running condition.

NLP means no line power or no line voltage. The drive thinks that there is no input voltage coming into the drive.
Check and verify the line voltage on L1 L2 L3 of the drive. Go to the MON menu and check the ULn Mains voltage to see what the drive thinks the main voltage is.
Verify DC bus voltage on PA+ and PC-. Compare your DC bus voltage readings divide by the square root of 2 to see if it matches the Mains voltage in the MON ULn display.
For example: For 230V rated drive the DC bus should read 324VDC.