Improve error feedback for blogs with no accounts set up

[vickychijwani]

Scenario: someone entirely new to Ghost signs up on ghost.org and creates a new blog, but forgets to setup an account by visiting myblog.ghost.io/ghost. Instead they try to login via Quill by entering their ghost.org credentials.

What happens now: one user reported that the login spinner never goes away. In my tests I get an error like "could not connect to myblog.ghost.io".

What should happen: inform the user that they haven't set up an account on the blog yet (link them to it).

Also is there a way to educate users on the difference between ghost.org credentials and blog credentials? It could be done with some explanatory text if the login process is broken down into multiple simple steps.