Just a quick update. The problem seems to affect only my new iPhone 15 Pro, with iOS 17.3.1. I installed the app on my iPad with iOS 16.3.1 and it works perfectly! Settings seem to be the same in both devices. iOS 17.3.1 needs some specific settings?

Always me … I searched a lot on the Internet and tried several solutions, but none of them worked. I even tried on my own “arguing” with shortcuts and finally I found a way to make it work. It sounds a little bit tricky, but for now it seems to be the only solution. I added an empty shortcut named “Comando rapido” (my iPhone is localized in Italian - “Comando rapido“ is Apple translation for “shortcut”). If I invoke Siri with “Comando rapido”, it asks me what command I want to execute and then I can specify my application command, which runs successfully. I cannot change the name “Comando rapido”, because any variation, even small, breaks the magic and again it doesn't work. If I add to “Comando rapido” my application command as the action to execute, nothing changes: if I invoke Siri with “Comando rapido”, it asks me what command I want to execute. It's not a great solution, but it works. I hope this can help