My UR44 input 5/6 not working in Cubase

Hi, I am using Cubase AI 12 on my Windows PC, I connected the audio from the computer into the input of UR44 5/6 as a stereo signal. I added a audio channel on the input 5/6 to be recorded, but when click the record button on the Cubase, there is nothing being recorded. Can someone help me?
I am sure there is an audio signal coming out from my PC.

From where does the audio from the computer is generated (internet source, other audio application…) - the UR44 or the onboard soundchip ? And how it is send outside of it ?

Additionaly, there is a ‘loopback’ function that could help re-sending an audio signal coming from an audio application working at the same time as Cubase (UR44 Operation Manual - p.14), which should make your present Line In 5/6 connection useless. Be careful to not make an endless audio loop, though, by carefully choosing both the inputs and outputs involved.

Thanks for the detailed help.
I am feeding the audio signal from the headphone out of the computer into the UR 5/6 input. Yes, I am trying to record music from playing music video in VLC player or the internet.
I will check the ‘loopback’ function as you mentioned to see if it is the culprit.

I have checked the loop back function on the UR44, it doesn’t make any difference if i chose ON or OFF on the loop back. 5/6 still not working

If the UR44 has a loopback function, it is quite possible that you don’t need the cable method to route audio from VLC to Cubase, as the output can be fed back to the input in the dspMix software.

You suggestion make sense because the UR44 is USB to the computer anyway but I don’t know how to route the VLC player to the Cubase.
I think I solved my issue of the 5/6 input. I checked the windows sound applet and put the playback option on ‘speakers/headphones’ instead of UR44 because that is how I cable from the PC to the 5/6 of the UR44.