Microphone doesn't work in multiplayer

[long quest]

This could be something really straightforward and stupid, but my mic doesn't seem to work in MP.
My keybind is set, and in the AUDIO setting, my headset with the mic is recognized and selected.
The Signal from Microphone sensor also recognizes surrounding audio, but when I try and talk in MP, people can't hear me.

[teal badge]

Zomboid Audio settings -- VOIP. Change from listen to activate by key or voice. Usually this is the reason