I was having the same exact problem, I think it has something to do with a Chromecast firmware update that was released 3 days ago.
It seems 1 of the creators has recognized the problem as seen over here
*Mathieu GosbeeLevel 5
11:40 AM (46 minutes ago)
That last update murdered our app, Videostream, and had to panic to fix it. This happens after every update.
These automatic updates that AREN'T being beta tested by Chromecast app developers have to stop.*