StageWave needs to work with the same configuration your audio device is using. So, if the audio device is configured for a different sample rate, StageWave won't work and will show the next message:

For fixing it:

1. Check that the audio device is configured with the same Sample Rate you are using in StageWave.
2. Check that the ASIO audio device is not being used by other audio software.

For example, the Behringer X32 needs to show the same sample rate you are using in StageWave, as the image shows.