Let's start from your Preferred Site URL.
Which is it ?
Go to Admin--> General and see the value.
Let's say it is : http://www.ask030.com/
On the Facebook dashboard put :
Settings ---> Basic panel :
App Domains = ask030.com
Site URL = http://www.ask030.com/
Settings ---> Advanced Panel :
Native or desktop app? = NO
Do you want to make this app and all its live features available to the general public? = YES
It's important that you check your q2a Preferred Site URL (Admin-->General) first.
Its value must be identical to the Facebook Site URL value.