airplay error 6700

Hi,

since today day (maybe earlier, but I don't know exactly when and I don't if something has changed in my netwrok) I get the Error 6700 when I am trying to play my music from Itunes on my Macbook via Airplay on a B&O Playmaker. I am sure, that it worked weeks ago. The devices are connected over a airport time capsule.

Does anybody knows this error?

Regards

Joerg