How do I fix AirPlay connection issue with Yamaha WX-010 speaker after switching broadband?

Hi,

I've just switched my broadband supplier and everything is working fine except for the connection to my Yamaha WX-010, wireless speaker. I normally do the setup through the Musiccast App on my iphone (as well the Wi-Fi setting on my Macbook Air) and after a number of attempts, I managed to get the iphone to see the the speaker and usually what happens is that the speaker then shows up on the Sound menu as the alternate to my Macbook Air but it ain't and I've run out of options.

[Re-Titled by Moderator]