Hello,
First, go to ¨Options¨ and under the Playback tab make sure you do have the correct playback device selected and that the programs volume is set to max and then click ¨OK¨. On the main page if you have a small window called ¨Channels¨ make sure both the ¨0¨ and ¨1¨ are blue, this means both channels are on. Then test again and see if you get audio. If you do not I think your next step is to contact NCH tech support. You can create a support ticket for them on the link below:
https://www.nch.com.au/support/index.html