I have been experiencing problems with my Dorico recently. When I reopen a project, there is an issue with the audio - no sound coming out from Dorico at all during input or playback.
In the preferences, I have the correct audio interface selected
The instruments are properly loaded in the Play tab, I can see the volume bars moving despite no sound being heard
The sound comes back after reloading the instruments (which, on a long run, is not sustainable!)
You do not say which VST you are using for your sounds. If you just updated Kontakt, it would have replaced the VST2 version with the VST3 version. I found (at least in one instance) I had to re-enter the instruments in Kontakt.
Thanks for the data. It shows that the metronome (DoricoBeep) is soloed and therefore all other instruments muted. Please open the Dorico Mixer (F3) and click the solo button of the DoricoBeep channel. Then you shall be able to hear all other instruments again.