social publisher, facebook, won't connect

Going crazy…
Trying to connect my blog to my facebook page but it won’t work.

When I click the link: Associate your WordPress account with a Facebook account
or in any way tro to connect to the facebook page I get this message:

Given URL is not allowed by the Application configuration.: One or more of the given URLs is not allowed by the App’s settings. It must match the Website URL or Canvas URL, or the domain must be a subdomain of one of the App’s domains.

Now I don’t know much so that only tells me something is wrong… Feels like I’ve tried everything and I really need this to work.

But if there is anyone out there who can help me I would be deeply grateful!

(I’ve had another blog connected to the same facebook page and that worked fine but now it just won’t work at all.)

Thank you!