I've bought a Roku Express for the sole purpose of being it able to use with my Echo Dot, now, everything so far has worked great, buuuut.... i've had problems opennings some channels, in my case those channels are: Disney+, Pluto TV and TV Azteca (a national channel here in Mexico).
When i tell my Echo, "Open Disney+ in Roku" just says (something that roughly translates to) "Obtaining Disney+ in Roku, i didn't found Disney+ in Roku).
I've tried a lot of combinations about how to say to open Channels, but it seems that saying "Open" is the only way that works.
The strange thing is that every other app works just fine, like Netflix, Youtube and Prime Video.
I hope that this is just some kind of strange behaviour on the app or skill side, and not something that is unfixable.