Noise when using Aux in on Yamaha N1 with Pianoteq

Hi.

I'm having problem with noise when I'm routing Pianoteq in to my Yamaha N1 using Aux in. The problem occurs both when I'm using the internal speakers and listening with headphones using the N1:s headphone jacks. The strange thing is that it only occurs when I'm launching Pianoteq and it is not present when listening to music from ex Spotify using the same computer and audio interface. My setup is a MacBook Pro 2017 with Apogee element 46 audio interface. Can anyone help me with this issue?