While AirServer does support Google Cast screen mirroring, AirServer does not support content casting from within applications (typically accessible by pressing the Chromecast button). This means that AirServer will not show up as a casting destination when pressing the Cast icon within apps like, for example, YouTube & Facebook.
With version 2020.07.09 of our AirServer Connect 4K UHD's software, we have added casting from within apps as an experimental feature. This functionality can be enabled in the Remote Management or the on-screen UI in the Google Cast settings. Please note that this functionality is currently only available on our AirServer Connect 4K UHD hardware solution.