This usually happens if you have entered the wrong details when you created the App in Facebook. Or have you changed a URL's of an existing App?Can you please recheck the settings of your APP in this page?
https://developers.facebook.com/apps
1) Check the URLs & paths are correctly entered and are pointing to the site where you have installed Ultimate Facebook plugin.
2)Select the correct App and click in the edit button.
Having a little difficulty setting up my Facebook login system. Currently, when clicking the button to sign up with facebook the button takes me to facebook and facebook displays the following:
"Can't Load URL: The domain of this URL isn't included in the app's domains. To be able to load this URL, add all domains and subdomains of your app to the App Domains field in your app settings."
Here's the problem.
I
f I click on "log in with FB button, here's what I get.
when I Sign In to Facebook developers, I put in the domain name, and I get the error below.
Answer Is Add Ur All Sub Domain Where U Place FaceBook Icon.
Comment Below If U Want More Information.
Thanking For Read This Post.
