I am developing a microphone app that uses the iPhone built-in mic as input and play the sound through Bluetooth-connected speakers. However, the sound output is not working as expected through the external Bluetooth speakers.

Below is my sample code.

do{
            let inputNode = audioEngine.inputNode
            let outputNode = audioEngine.outputNode

            let format = inputNode.inputFormat(forBus: 0)
            
            inputNode.installTap(onBus: 0, bufferSize: 512, format: format) { (buffer, time) in
            }

            audioEngine.connect(inputNode, to: outputNode, format: format)

            try audioEngine.start()
        } catch {
            
        }

I tried with above code but I only can hear the sound from iPhone speakers.

Please advise what are the changes I need to do my code.