iPad 1 not visible for other devices through Connect

[seninha]

My iPad 1 running on iOS 5.1.1 (latest spotifiy app from Aplle store) is somehow not visible for my other devices when I want to use Spotify Connect.

iMac does see my Android phone, and phone does see my iMac without any problem.

All devices are connected to the same home wifi connection.

Does someone have any idea how I can make it possible to control my ipad 1 from my phone or iMac?