Casting icon not appearing on Youtube website to cast to Sony KDL-65W855C

[latexjeans30]

Good moring all,

                              I have one of my devices (computer to Sky Q box) "paired" so when watching a YouTube video through the website on my computer (Windows 10, Microsoft Edge) I am able to cast the video using the YouTube app on my Sky Q box. 

The problem kicks in when I use the YouTube app (signed in with my details) and after looking at the help setion it states different rules for casting to an Android TV. In this case Sony the above mentioned model-number. I go in to the YouTube app on my TV and when looking for the cast icon to try and cast the video from my computer to the app there is no cast icon. On the YouTube app on the TV version there is no "pairing" option in the settings menu likewise the TV does not show up on the settings on the YouTube website. The TV and the computer are on the same WIFI network and have searched for the last week or so to try and find an awnser and so far have come up with nothing. 

If this has been asked before please accept my apologies. I am quite new to Android (I have been a Windows man for too many years) so any reason someone could give why it won't allow me to cast from website to TV app or if there is a soloution (maybe even both) I would love to hear it. 

HAPPY MAY DAY! 

[rooobb]

Have you already tried using Chrome and its google cast extension?