PT 11.2.2 and airplay engine: question about cable/wireless

I boys, I installed the demo version of PT 11.2.2 on my Macbook Pro Late 2008 (2,53 Ghz Intel Core 2 Duo/8 Gb Ram) with Osx 10.9.5.

Before to buy it, I tried to set engine on Airplay so I can listen my PT project on my stereo hi-fi (my hi-fi ampli is connected on home-net with ethernet cable). But I can do it just if my notebook is connected to the net by cable and NOT by wireless (if i connect with wireless I can't see "airplay" into engine menu).

Is that a bug or it's just impossible to do?

Any solutions?

Thanks and sorry for my bad english ;)