I had constant problems trying to use my chromecast with a BT home hub 3.
I would turn the amp to the Chromecast input and the screen would show it was connected to the BT home hub. Then none of my phone (android - lollipop), Nexus 7 (ditto), wife's phone (android kitkat) could find the Chromecast. And they key connecting to the Chromecast as a wifi signal. Resetting did nothing
I ended up having to re-set the router (with a paperclip), delete and re-install the chromecast app and reset the chromecast (hold in the button on it for 20 seconds). Then it worked okay, for a week, then I had to repeat. Been with Plusnet for a month and not a single issue.
Also (a separate issue I've had - but only a minor grumble is) I would find that most apps (BT, Blinkbox and even Play movies) would not have a "cast" icon, when they clearly should ahve. I had to go through the process of casting from youtube - which never dropped the cast icon, then re-try to cast the thing I wanted to cast.