GPIB-USB-HS+ not return the *IDN? string

Hi All

Recently we purchased two GPIB-USB-HS+ units and it does not return the *IDN? string
while some (purchased earlier/same model) return the *IDN? string.

I used the same instrument(Anritsu Synthesizer MG3694B)/setup to verify the *IDN? string while some return
and some don't return.
I tried GPIB-USB-HS+ and GPIB-USB-HS as well.
Also I tried installing the latest driver (Version:NI4882_1760f0) and old versions.