I am also having problems with audio not working on video calls.
I can hear my contact but they cannot hear me. They can see me on video.
I have checked all the settings and the laptop internal mic is listed as being connected and working. During the Skype video call the green bar rises and falls when I am speaking and stop. But the contact hears nothing. This has happened in a call to a second contact ,too. So it is on my end.
The audio worked on the first call to the contact mentioned first but not since.