Audacity is not recommended for recording a Skype interview.
Your local voice is a service of the computer, so that usually records just fine. The far side voice is a service of Skype and they do not share well. You may have also noticed what you’re really recording is the Skype bubbly cancellation voice, not the real performance. That’s normal.
I did it with two computers and a mixer, but if you don’t want to go that way, you can try one of the Windows Skype software packages such as Pamela.
http://www.pamela.biz/en/products/
Also.
https://forum.audacityteam.org/t/help-recording-with-a-mic-laptop-and-headphones/35068/6
Koz