No MIDI in Studio One 5

I’m sure it’s a noob issue but I see no MIDI input in Studio One.
I created an instrument track and and added Scaler as an insert. I get MIDI on the armed track and Scaler sees my keyboard but MIDI notes are not reflected on the scaler keyboard. Scaler is monitoring MIDI, not audio.
Anything obvious to check.?

User error. Solved. Output routing issue.