Hi
Since I installed the latest version of Dragon (55.0.2883.59), my Chromecast no longer works.
I tried it with Chrome and it works fine. The problem is that of Dragon.
Does somebody have an idea ?
This may help answer your question.
Casting a Chrome tab or entire desktop
Google Cast is now built in to Chrome
I think I have found the explanation. There is no more extension available to run the Chromecast. The application is directly integrated with Chrome, as can be seen from the link above.
That’s why my Chromecast no longer works with Dragon.
Unfortunately, I’ll have to give up Dragon. 
I have both opera and vivaldi, they both chromecast built in.