When I initiate a Rainbow audio or video call, the call is not initiated and an error is displayed indicating: webRTCWarning No media is available. Please check your camera/microphone availability.
This problem occurs because the Rainbow Desktop application is not allowed to use the PC's microphone or camera.
It may be a problem with the privacy configuration of Windows 10 or also that the use of the microphone and/or camera is blocked by the antivirus application installed on the PC.
How to fix the issue
Open the menu Microphone Privacy settings
and check that the setting "Allow desktop apps to access your microphone" is set to ON
Same for the camera, open Microphone Privacy settings
and check that the setting "Allow desktop apps to access your camera" is set to ON
Mainly all security softwares have now privacy features to block the access to your microphone and camera.
Please refer to your antivirus application documentation to know how to change the privacy setting to allow the access to your microphone and camera.
For AVG see the menu "Data protection"
For Bitdefender: see the menu "Privacy"
For Kaspersky: see the menu "Protection"
For Eset Internet Security: see the menu "Computer protection"