Sidechain with fab filter pro c?

Hey guys wondering if anyone can help me with side-chaining in abelton with fab filter pro C



I have a ghost kick setup that I have then selected my audio to go to the track which I want to sidechain and I have selected the audio input on the ghost kick where it says Fab filter side chain.



Then on the pro c I have sidechain on and have selected ext in. not sure which step I am missing to get it to work?



Any help would be much appreciated.