Setting Up External Compressor

I am having problems setting up my external compressor to Cubase via the Saffire Pro 24. I’ve routed output 3 and 4 of Saffire into Input 1 and 2 of the compressor, and from the compressor I’ve routed out into Input 1 and 2 of the Saffire.

In Cubase VST Connections, I’ve set Input to be Input 1 and 2, and in Output I have Stereo bus 1 (Saffire output 1 and 2) and Stereo bus 2 (Saffire output 3 and 4).

I imported an audio file and set that output to Stereo bus 2 and created one more Stereo track with input 1 & 2 and output to Stereo 1. However I then get no sound coming to my monitors. But when I switch back to Stereo bus 1 on the track with the audio file I imported, there is audio playback coming out of my monitors.

Is there something I am not doing right here?