Can't get rid of network background on sound?

Question

macbook

I bought a hama Vga - Type-C adapter, connected it to an external monitor, there is a picture but there is a network background on the sound output, my computer is MacBook Air M1

Answer 1

I'm assuming an external monitor allows you to play sounds. If so, then no sound is transmitted through VGA, just turn off the sound on the monitor. Or use a different input, but it may not start anyway.

Answer 2

The sound from the macbook gave from the headphone output to the mixing console and from the external sound card. The picture comes out but because of the sound connection, a network background appears. How to remove the network background?