Dennis is an audiophile and he's having issues playing music from smartphone using Google Chromecast. It wants him to upload all his music to the cloud first. Leo says that his casting app may be corrupted. He should try another one, like AllCast. From the chatroom - Google requires you to upload your music to the cloud before casting with Google Play. That's what it's designed for: to play from the phone at home using the Google Home App.
Damian is trying to get an app called AllCast to work on his PC with AllCast Receiver, but it won't work for him. It works on his brother's PC, though. Leo says that AllCast is a great program that allows you to cast to it through Chromecast and it was designed to work with any streaming player. You can even turn your PC into a Chromecast like device. It's kind of a hack, though, so it may not work consistently.