There are several reasons why audio cannot be played. It may be the graph connection, RealMotion, Window and the audio device. Here are the principal tips to trouble shoot:

1. Make sure that the hardware device is properly connected and turn on. If no hardware device is connected, RealMotion will create a virtual device, but a hardware device is required to output audio.
   
   
2. Check the audio levels in Windows:
   1. Run the graph playing an Audio file.
   2. Go to the Windows Start Menu and search for "Volume" 
   3. Open the Volume Mixer
   4. Check if the Volume is not set too low
      
      
3. In the System Configuration (F9), verify that the Sound System is valid.
   
   1. OpenAL is the default Sound System, but it needs an audio output to be active.
   2. Asio is another Sound System that enables ASIO4ALL or Dante protocols:
      1. ASIO4ALL can be active without any audio output on the server, but only one program can play audio at a time.
      2. Dante requires a Dante PCIe Card, or a Dante Virtual Sound Card and can send audio over network.
         
         
4. Verify graph dataflow:
   1. Select the AudioOut boxin your graph
      
   2. Add an Audio Player box and connect it to the AudioOut box (this will disconnect the current source of the AudioOut box)
   3. Run the project
   4. If you can hear audio, this means that there is an issue with the audio data source: 
      1. Verify that an AudioOut box is connected to an Audio Line or an Audio datatype.
      2. Verify that the Audio flow and/or Audio-Video Line flow is continuous until a Video Player, an Audio Player, or an Audio Line In box.
      3. Verify that the volume in the content boxes and in any Audio Mixer is not at zero.
      4. Go to the Audio Out properties and check if an audio device is selected.