title: CMSensorRecorder is not authorised, but I am never prompted to give authorisation?
body: <p>I'm making an app that will record user acceleration for a duration on the Apple Watch and send that data to the paired iPhone. I'm using the <code>CoreMotion</code> framework to achieve this.</p>
  
  <p>My issue: I've been using a <code>CMSensorRecorder</code> object to record the data. This worked for a while, but <code>CMSensorRecorder.authorizationStatus()</code> is now "not authorised".</p>
  
  <p>I've had a <code>NSMotionUsageDescription</code> in the <code>info.plist</code> files of both the watch and phone apps since the beginning. I've removed and re-added these, with no luck. </p>
  
  <p>I recall the app displaying a prompt to allow motion tracking, but can't recreate the ability to display the prompt. Would greatly appreciate any advice on how to enable <code>CMSensorRecorder</code> again. Cheers.</p>
  
  <p>My code initialising <code>CMSensorRecorder</code>:</p>
  
  <pre><code>if CMSensorRecorder.isAccelerometerRecordingAvailable(){
              if CMSensorRecorder.authorizationStatus() == .authorized {
                  print("\(Date()): recorder started")
                  DispatchQueue.global(qos: .background).async {
                      DispatchQueue.global(qos: .background).sync{
                          self.dateStart = Date()
                          self.recorder.recordAccelerometer(forDuration: self.duration)   
                      }
                  }
              }
              else {
                  print("\(CMSensorRecorder.authorizationStatus())")
                  self.xAccLabel.setText("not authorised")
              }
          }
          else {
              print ("Recording not available")
              self.xAccLabel.setText("Not available")
          }
  </code></pre>