Sound Sliders not working

Hi,

I’m about to setup a menu for my project. Everything works so far except the sound sliders in my option menu.
I have a widget blueprint and implemented two sliders with the on value changed event.
But when i change the values via the slider nothing happend except the cast fail. I tried to cast the two sound sliders to Audio Component SFX and Audio Component Music. See attached picture.

What am i doing wrong?