DC Under Voltage and Over Current

See the "Trouble Shooting" section of the operator's manual.

There you may find the reason.

Or contact the manufacturer.

This is assuming that you have no one on staff that knows how to operate the equipment.

As you stated, "the drive supply is healthy"

Your DC under voltage message could mean that your AC to DC converter is broken and therefore you are not fully charging the capacitor based storage system.

The "over current" message would be a result of the drive trying to compensate for the lower voltage of the stored energy in the capacitors. The drive will take more current from the stored energy in an attempt to meet the power requirements, but the internal settings for current limits will stop the attempt.

You could also have a phase loss at the incoming power feed due to a loose connection, but you should probably have an error message about incoming power problems. If not, then the problem is inside the drive. Time to send it out for repairs.