Hey, have you tried to select the audio device on the 'capture device' settings? There's a "video mode" menu, with your web camera, or tv capture, if you have one, and an audio, with the options "none", and "the name of your mic".
I'm having similar problems. I tried both: Casting my screen and casting a file. Open with: another device (my phone, same wifi), another vlc instance on same computer. I tried using :8080 at the end ot Ip. Nothing worked. Instructions I got were as follows: https://tecnoblog.net/290759/como-transmi...