I want to play back a score, but there is no sound. All notes are visible in the piano roll in the playback window, but nothing is coming. I have substituted the preset Halion Player, or engine, whatever it´s called with BBCSO plugins. Now the sound does come, but only from one single instrument, a flute. I have loaded several, and wonder how I can activate the other loaded instruments for the subsequent instrument in the score. I checked the midi channels, but also there is no desired response. I probably (once again) missed some secret button in Dorico at the end of its universe… 
You have not said what version of Dorico or what computer operating system and version you are using (or what computer you are using, since the Apple M1 chip could make a difference), but my first suggestion would be that you reapply the Playback Template (for HALion, for example) in Play mode.
Oh, yes, sorry: Dorico 3.5 on Mac Monterey 12.3.1. It´s not an M1 chip, I guess. And thank you, I´ll try out your suggestion!!!
Hi @ulfmanumusik , if you still have the non-sounding version of the project, you could send it to u dot stoermer at steinberg dot de and I can have a look and see what might be wrong with it.
Thanks, Ulf!! I´ll do that!