No playback sounding

Dorico newbie here, please be gentle.

I don’t hear any notes, not when doing MIDI input, not when doing playback. It worked earlier today, now it stopped working, and I don’t know why. I’m trying to learn why so I can fix it myself in the future.

I do hear the metronome. MIDI is arriving into Dorico (I can MIDI input notes – I just don’t hear them).

I’m attaching screenshots of (what I believe are) the relevant preferences, which seem to be set correctly. My audio interface is correctly selected too.
Screen Shot 2020-04-06 at 3.59.02 PM.png
Screen Shot 2020-04-06 at 3.58.48 PM.png

Did you accidentally mute everything? Try going to Play mode, and from the Play menu choose Deactivate All Solo States, and do Deactivate All Mute States for good measure. If that doesn’t help, try opening the Playback Devices dialog, and double-click the ‘HSSE (Elements)’ entry in the list to reapply the default playback template. If none of that works, please zip up and attach your project file here so we can take a look at it.

Solved: once I opened up HALion, no sounds (patches) were available. How strange. I’m so sure this was working earlier, unless I’m dreaming things. I am going to re-download the sounds installer via the Steinberg Assistant.