Unable to add output for iOS custom camera - ios

Question

Up until recently, my custom camera was working fine. However, I have recently been receiving an error (perhaps with the upgrade to Xcode 8.2 and 8.2.1). I have the following code for loading the camera:
func reload() {
captureSession?.stopRunning()
previewLayer?.removeFromSuperlayer()
captureSession = AVCaptureSession()
captureSession!.sessionPreset = AVCaptureSessionPresetPhoto
let captureDevice = AVCaptureDevice.defaultDevice(withDeviceType: .builtInWideAngleCamera, mediaType: AVMediaTypeVideo, position: direction)
var input = AVCaptureDeviceInput()
do {
input = try AVCaptureDeviceInput(device: captureDevice)
} catch {
print("error")
return
}
DispatchQueue.global(qos: .default).async {
if self.captureSession!.canAddInput(input) == true {
self.captureSession!.addInput(input)
if self.captureSession!.canAddOutput(self.cameraOutput) {
self.captureSession!.addOutput(self.cameraOutput)
self.previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
self.previewLayer!.videoGravity = AVLayerVideoGravityResizeAspectFill
self.previewLayer!.connection?.videoOrientation = .portrait
self.previewLayer?.frame = self.bounds
DispatchQueue.main.async {
self.layer.addSublayer(self.previewLayer!)
self.captureSession!.startRunning()
self.clickedImage = nil
self.bringSubview(toFront: self.rotateButton)
}
} else {
print("cannot add ouput")
}
} else {
print("cannot add input")
}
DispatchQueue.main.async {
self.bringSubview(toFront: self.rotateButton)
}
}
}
For some reason, it keeps print "cannot add output" in the debug logs. I have tried to resolve this using this SO post, but it still does not run properly. Does anyone know what this means and how to fix it? Thanks!