Chromecast built-in

Hi there, I have the U1 unit, I installed the chromecast built-in program, but I think I need the especific apk, because it seems on the net, but it doesn work is I send a video to it.

Some one know if there is a solution?
Thanks.

Enviado desde mi VOG-L29 mediante Tapatalk

Won't work. The U1 is not a Google certified Android TV.

This app works pretty well. It emulates Google's casting protocols and allows you to screencast (from the Google home app), cast YouTube and cast Google play music. Keep in mind that there is an in-app payment.
https://play.google.com/store/apps/details?id=com.softmedia.receiver.castapp