Attaching an audio file into MSMessage

Question

I want to attach an audio file into a user's iMessage window. My code is quite simple:

func chooseSound(tapName: String) {
    if let ac = activeConversation {
        if let urlPath = Bundle.main.url(forResource: "bell", withExtension: "mp3") {
            ac.insertAttachment(urlPath, withAlternateFilename: "bell") { error in
                if (error != nil) {
                    print (error?.localizedDescription ?? "some sort of error")
                }
            }
        }
    }
}

Xcode crashes with no explanation with the insertAttachment line.

This is with my personal (now getting old!) Intel Mac, which can only run Xcode 14.0.1. On an M1 chip running Xcode 14.3, this actually works. Why is this? Is it my code, the Xcode version, the Intel chip?