Connect amp not playing rca input

Hi I recently bought a connect:amp to replace an old Cambridge audio a5 amp which I used to listen to vinyl. I have 2 technics 1210s which play via a pioneer dj 300 mixer.these were hooked up to my old amp which powered 2 4ohm speakers perfectly fine. However I wanted to be able to utilise these speakers for streaming music and also to stream my vinyl to other areas of the house. Therefore I bought the connect :amp thinking this would be a very straight forward process of replacing my old amp with the connect amp. I have the mixer connected to the connect amp via rca and I cannot get any sound. When I stream music through the connect or link it with my Playbase the 4 ohm speakers work perfectly fine. Any idea why the connect amp won't play the rca input. As far as I'm aware the mixer acts as a pre-amp so can't understand why I'm not getting any sound. The mixer clearly shows that a signal is coming from the channels were the turntables are playing