U2417H, no sound

I purchased two U2417H monitors a week ago for my new build computer. I'm unable to hear any sound, even though I can see the monitors are recognized by Windows 10 and it shows that sound should be playing (see the picture below). They're connected by mDP to DP cables from the monitors to the GPU. However, I've also tried DP cables and HDMI cables and I'm having the same problem with those as well. I've tried just connecting one monitor and it still doesn't work. I'm sure it's a simple fix but I can't figure it out for the life of me. I've tried using headphones in the front jack and sound works fine from there. Also tried all the different options found in 'Sound' on Windows 10. Picture showing sound should be playing: i.gyazo.com/a0c66aa39fc936e1423379393775dc10.png

Appreciate any help!