Since Facebook already updated their app API, may i know do you have add these 2 oauth redirect URI into your current Facebook app?

You can check my attached screenshot below.

if the issue still persists after you added those oauth redirect URI in your Facebook app, can you update your following site details at http://stackideas.com/dashboard/site so we can better have a check?

- Joomla backend access
- FTP access
- Facebook access