The in current on a single phase is much lower than the other 2 phases.
To verify if the issue is the VFD or the incoming power, first rotate 2 of the phases on the input of the VFD terminals. If the problem remains on the same phase of the VFD, then the VFD is the issue. Is the VFD is inoperative ? If yes, then you will need to check the input rectifier, replace the input diodes if applicable or replace the VFD. If the problem follows the rotated phase then the problem is with the incoming power. Check the connection on the incoming power and resolve the issue with the incoming power or transformer..