Fluke instrument not found on NI MAX (even though it had previously worked)

Hi,

I have connected a Fluke 5502E to my computer using GPIB-USB-HS+ cable.

Next I tried to detect my Fluke 5502E on NI MAX using the following steps:

My System -> NI GPIB-USB-HS+ "GPIB0" -> Scan for instrument.

But no instrument was found during the scan even though the Primary Address on NI MAX is the same as the instruments GPIB Port Address.

This is confusing as NI MAX had previously found the instrument and this only stopped working after I had connected a second instrument using a separate GPIB-USB-HS+ cable.

Would anyone be able to guide me on how to fix this?