midi routed to vst rack not routing through to audio

There is no sound coming through the midi track > VST rack instrument > instrument audio track.

The output chain is legitimate (as above - I have checked in the editor window), but no signal/metering and no sound on the output audio track.

Nothing seems to be amiss in the preferences, settings, etc.

Is it down to Cubase having a bad day??

A few things to check…
MIDI channel matches from track to VSTi?
Output of instrument is enabled (especially if not the default output or output 1).

Is monitoring enabled ?

Can be the case sometimes, but mostly it´s down to user not knowing what he´s doing…
MIDI through active…? Filters set?

User was having a bad day… =D
The full story was I was trying to feed a sequencer through the vst rack instrument, and was just learning what its notes were, because it is not a chromatic scale. It finally triggered some notes as intended.