Chromecast will not work with Optus. I can chromecast other apps to my TV but Optus Sport does not work. I can view it on my phone but when I press the cast button it does not work. Am an elderly lady so any advice would be grateful.
Sounds like you are doing everything right since the other apps are able to cast without any problems. I suggest you delete and then reinstall the Optus Sport app and see if that helps.
If not, you may want to reach out to their support and see if they have any known issues with their app.
Thanks for posting-