UWP SerialDevice.FromIdAsync throws "Element not found" (Exception from HRESULT: 0x80070490) on Windows 10

I want to open serial port on an attached Bluetooth device in a Xamarin Forms application.

Here is the code (I simplified it in order to illustrate the problem):

  string l_gdsSelector = SerialDevice.GetDeviceSelector();
  var l_ardiDevices = await DeviceInformation.FindAllAsync(l_gdsSelector);

  foreach(DeviceInformation l_diCurrent in l_ardiDevices)
  {
    if(l_diCurrent.Name.StartsWith("PX05"))
    {
      m_sdDevice = await SerialDevice.FromIdAsync(l_diCurrent.Id);

      break;
    }
  }

This code throws "Element not found" (Exception from HRESULT: 0x80070490) Exception at await SerialDevice.FromIdAsync

I cannot believe it : "Element not found" whereas DeviceInformation.FindAllAsync juste returned it as an existing device !

Can someone explain me this strange behavior? and predominatingly how to solve it?

Thank you in advance

The first call to DeviceInformation.FindAllAsync function must be made in UI thread. as this code is a part of a DLL, I decided to always call it in the UI thread.

So here is my modified code :

  TaskCompletionSource<bool> l_tcsResult = new TaskCompletionSource<bool>();

  await Windows.ApplicationModel.Core.CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
    Windows.UI.Core.CoreDispatcherPriority.Normal, async () =>
    {
      try
      {
        m_sdDevice = await SerialDevice.FromIdAsync(p_strDeviceID);

        l_tcsResult.SetResult(true);
      }
      catch (Exception l_exError)
      {
        l_tcsResult.SetException(l_exError);

        System.Diagnostics.Debug.WriteLine(l_exError);
      }
    });

  await l_tcsResult.Task;

To allow application to communicate with serial device, please edit package manifest and add following entry in <Capabilities> section:

<DeviceCapability Name="serialcommunication">
  <Device Id="any">
    <Function Type="name:serialPort" />
  </Device>
</DeviceCapability>