Google OAuth 2 authorization - Error: redirect_uri_mismatch

Question

On the website https://code.google.com/apis/console I have registered my application, set up generated Client ID: and Client Secret to my a

Answer 1

If you're using Google+ javascript button, then you have to use postmessage instead of the actual URI. It took me almost the whole day to figure this out since Google's docs do not clearly state it for some reason.