Virtual Instrument Problem in Cubase 11 Pro

Greetings! Brand new to Cubase coming from another DAW.

I’ve been learning well for the past few days… Produced a few compositions… It’s going well.

Until today. Periodically, I’ve been getting stuck MIDI notes and a few instances of (what I’d describe as) as micro-second audio loop that gets stuck.
The only way out that I’ve found is to close\re-open Cubase. It sucks - but not the end of the world.

When I close and re-booted today, I came back to my project and none of my VST virtual instruments will sound.

MIDI triggers the appropriate Kontakt instruments… and I get blue feedback on the track and on the Mic Console.

Regular audio tracks play fine.

But none of my VSTs are sounding.

I’m on Win 10 \ Cubase 11 Pro \ Scarlett 6i6 \ 32 gig RAM

I have a long history of clicking or unclicking the wrong box in some setting menu somewhere… but I’m absolutely lost.

Any thoughts or ideas would be greatly appreciated!