Problems granting external permission on facebook

I am working on using this ultimate FB for my blog exanderson.pulsohispano.com. Using domain mapping I have exanderson.com pointing to aforementioned blog.

I am unable to "grant extender permission" when setting up ultimate fb settings.
I have used both http://exanderson.pulsohispano.com and http://exanderson.com in the fb api for website url.

The error message I get is:

Invalid Argument
Given URL is not allowed by the Application configuration

does my problem stem from the domain mapping?