Well I’ve hit the URL and received the JSON string back properly from what I can tell. I doubt it’s a firewall issue, etc as I’ve never had an API issue with this hosted wordpress. I did see that page and nothing on there looked like the issue I was having.
I DID in fact just update the WordPress to the latest version (4.6 I believe). I don’t see an update or your plugin which I have installed (4.0.2). This is the first time I attempted to install though.
I’ll keep digging…
I am having the same issue this morning as well. I pop my API key in and hit save and it just goes back to my home page of my site. When I get back into the Admin section of wordpress the key is gone and it’s not connected.