I had the same problem. the error log is sketchy. this solution:
1st goto WEBSITE (below SELECT HOW YOUR APP CONNECTS...) and click 2nd in the text area, fill in your website http://www.yourdomain.info 3rd go back to APP DOMAIN (BASIC INFO) and type yourdomain.info
It absolutely works, but I did not quite understand the instructions, so I am going to recount them for other neophytes like me.
On the Facebook development page “Apps-YourAppName,” click “General” in LEFT Nav.
There are 3 sections on this page: “Basic Information”, “Cloud Services” and “Choose how your application integrates with Facebook”
In the "Choose how your application integrates with the Facebook section" section, select "Website"
Enter your fully qualified domain name in the website URL dialog box. Example: http://www.mydomain.com OR http://mydomain.com (my site does not include www, so I did not add it).
At the bottom of the page, click the "Save Changes" button. You may be notified that it may take several minutes for blah blah blah ... but you can continue the following steps immediately.
Now in the "Basic Information" section at the top of this screen, you can add your application domain. This should be formatted as mydomain.com. Do not add "http: //" and do not add "/" at the end of the domain name.
NOTE. My site does not use www, so I can’t confirm that it is required in step 6. Try it in both directions if you are not sure.
At the bottom of the page, click the "Save Changes" button. You may be notified that it may take several minutes for blah blah blah ... but you can continue the following steps immediately.
At this point, the error is NOT displayed as it was before.
Hope this helps!