I'm trying to change the volume level on my Ubuntu 16.
If I try to mute via holding the notebook's "Fn" + "volume down" key, the volume decreases 1 level and then it quickly decreases the rest of it, as expected.
If I try via USB Keyboard (I have a Microsoft Natural Ergonomic Keyboard 4000) holding the volume down button, it only decreases one level. That means I have to press it over and over until the volume is muted. Same thing happens with Volume Up key.
Any ideas on why this is happening and how to fix it?