Track can be heard in Cubase but not mixdown

I’m on Cubase 11. I’m using the plugin Synthesizer V Studio, but I’m using just normal MIDI instead of the built in editor to make just something that sounds vocal-adjacent, which may be the problem. I just, don’t know how to fix it. Everything sounds fine when I play the song in Cubase, but when I mix it down, the Synthesizer V track isn’t there. It is routed to stereo out. I want to send the demo to my friend, but I’m really confused… Anyone know how to fix this?

Can you explain in more detail what you mean by this? What does ‘normal MIDI’ mean?