The typical problem for most is that you need to select the stream audio source and set its level. The source used for streaming is NOT the same as you hear on the computer doing the streaming.
The exact syntax of the commands/labels depends on which OS you are using, but the procedure is the same. Right click on the speaker icon in your taskbar and select "record properties". From there select the correct input .. and set the level.
I strongly suggest that you use a digital level meter to monitor the audio you are streaming. That is what I use and how I set the levels. If scanning a bunch of frequencies, just make sure none is too hot.
Version 1.4 on this page or
The meter I use is from Darkwood.