--06 stands for NST is not a fault but means the drive is in an freewheel stop condition.
Causes and fixes :
1. VFD has an input assigned to Freewheel stop?   Check to see if that the input is active.
2. The drive is in 3 wire control (201 =3C). LI1 must be active before the NST will clear.
3. The VFD is in 2 wire control (201 = 2C) Verify if the drive was powered with the run command active, if so cycle the run command or set 202 to 01 (LEVEL) IO menu, 2 wire type = level
4. If the drive is being controlled by serial communication, the drive will display --06 until the Hex value of 6 has been written to the command word.
5. If the 4-20 mA signal loss is programmed to freewheel stop and the drive has loss the signal. Check the 4-20 mA signal.
6. If the drive is running from terminal control  and the stop button on the keypad or remote display is pressed, the drive will go to --06. Power cycle the drive to clear the --06.

Released for: Schneider Electric Hong Kong