…I’m not able to send the *first* play to the score, (hope to be clear).
Oh, you are saying that Iannix responds to subsequent OSC-play messages, but not when the *initial* play is from OSC. If that is true, I likely would never have noticed this myself because during all my tests I would have done at least one play from the UIF. I’ll have to look at that!
What happens if you do a /iannix/stop or /iannix/fastrewind first, then the /iannix/play? (a kind of throat-clearing:–)