Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Most of the Android casting re:Roku (from Cast icon on Android mobile device) is limited to those things that are either Chromecast compatible or the like. (Youtube or other sites that show cast icon). Check to see if you can cast Youtube to your Roku from your Android. (If so, then working). Simply being on a webpage and pressing the Android Cast icon likely won't work for most sites with the Roku.
With my Android Phone, I use Web Video Caster or Castify or Rokify apps from the Play Store to cast everything else regarding online streaming or other files.
Roku Community Streaming Expert Just another Roku user... I am not a Roku employee. Insignia RokuTV, Ultra 4660x, Premiere+ 3921, Express 4k+ 3941
Most of the Android casting Roku from Cast icon on Android mobile tool is restrained to those matters which are both Chromecast like minded or the like. YouTube or different websites that show cast icon. Check to see if you could cast YouTube for your Roku from your Android.