I have an Express+ and I have been trying to mirror my Laptop (Google or Firefox) to the Roku. It doesn't seem to find anything. Under devices, it says "none" and a message under that saying always blocked devices. Why would it say that, if the feature is available. Any idea if this feature will work? I have cast my Laptop and Chromebook via the Chromecast easily, but with the Roku, so far no luck. Thanks for any advise.