How to reset nudrive inhibit LED?

I have a nuDrive power amplifier and right now, the INH status LED is on. 

Manual says, "This is the inhibit status LED (labeled INH). If a motor does not move when commanded and this LED is on, check that the nuDrive is enabled via the ENABLE switch, host interlock and external inhibit inputs, and not in an E-Stop condition."

I have done all the the above but the LED is still on. Is there any way to reset it. 

Thanks for your help.

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