iOS 10.0 Speech Recognition Error kAFAssistantErrorDomain

I try using speech recognition as below

    let urlpath = Bundle.main().pathForResource("myvoice2", ofType: "m4a")
    let url:URL = URL.init(fileURLWithPath: urlpath!)

    let recognizer = SFSpeechRecognizer()
    let request = SFSpeechURLRecognitionRequest(url: url)
    recognizer?.recognitionTask(with: request, resultHandler: { (result, error) in
        print (result?.bestTranscription.formattedString)

    })

The result is nil, I debug and see the error as below

Error Domain=kAFAssistantErrorDomain Code=1101 "(null)"

Do you have any idea?