Workaround, if any
Onyx Virtual Camera may not be recognized by Skype, if there is no other USB or built in camera present.
Try to connect a local USB camera.
The Skype connection status may take long time (up to 10 seconds) to report a failed Skype call.
If an IP Cam address that does not exist is mapped to display plane, Onyx may take up to 20 seconds, before the other valid streams are shown.
If windows "Stereo mix" is configured to mix mic input and audio output to record Skype conversation with Onyx and speakers are used for audio output, you may notice audio echo.
Use a headset instead of speakers.