Given URL is not allowed by the Application configuration Facebook application error

Try to check at Settings > Advanced. At Valid OAuth redirect URIs, make sure you have a correct domain.

Hope it works.

You need to add the URL to your app:

1. Go to the app, you want for user login, on the Facebook Developers page
2. Click on the settings tab
3. Click add platform
4. Select Website
5. After selection it will ask for some details such as URL for your website which uses login with facebook feature, fill the form and submit it

That's all and you are done. Make sure that the app's URL is the same from where you're logging in.

Under Basic settings:

1. Add the platform - Mine was web.
2. Supply the site URL - mind the http or https.
3. You can also supply the mobile site URL if you have any - remember to mind the http or https here as well.
4. Save the changes.

Then hit the advanced tab and scroll down to locate Valid OAuth redirect URIs its right below Client Token.

1. Supply the redirection URL - The URL to redirect to after the login.
2. Save the changes.

Then get back to your website or web page and refresh.