Double audio signal

I’m using Cubase 10 on a Mac with UA Apollo Twin DSP sound card. I just bought a Moog Subsequent 37. I have connected the Moog to the mac via USB and to input 1 of the sound card, then created a MIDI device and added it as an external instrument in audio connections.
But when I add the instrument track and play something on the synth, I hear a double signal - it plays from the track AND directly through the soundcard or gets monitored through Cubase or something - at the same time! The monitor-button in the channel settings are turned off.

Can someone please tell me how to fix this? I’ve browsed through the internet for a while now and I can’t find a solution. Any help is very appreciated!

Browse through the Apollo manual for a while, and learn how to disable the direct- / hardware monitoring of the Apollo.

I’ll try that, thanks a lot!