Login through facebook omniauth OAuthException 100
===

the setup is Rails 3.2.6 + Devise + omniauth-facebook .. i followed the Devise wiki but when trying to login with facebook account i get the following error 

{"error":
{"message":"Code was invalid or expired. Session is invalid. This could be because the             application was uninstalled after the session was created.",
"type":"OAuthException","code":100}}}}

I tried changing the host to no avail. it's not invoking the callback even, just not working. 

this is the first run ever on a dev machine, so I don't think anything got to go invalid yet.

thanks in advance