Apple TV 4 isn't seeing my Airplay speakers

[boston04and07]

Hi guys - having a weird problem and was hoping someone could help me. I have an Apple TV 4 and a pair of bookshelf speakers plugged into a latest generation Airport Express in the next room. The Airport and Apple TV are both running the latest firmware and/or software. However, the Airport speakers aren't showing up in my Apple TV's audio output menu. I can AirPlay from my iPad and iPhone to the speakers just fine, so I can't figure out what the issue is.

I'm positive I Airplayed music from my old Apple TV 2 to these speakers not too long ago...if anyone has any ideas I'd love to hear them!

Edit: my main router is a latest generation AirPort Extreme, btw, if that makes any difference...

 

[profets]

Strange. Do you have any other Apple TVs in the house, and if so do they show up as options for AirPlay from the Apple TV you're referring to?