ruby on rails - Facebook OAuth Callback redirected to API not supported -

i'm trying register users through api using facebook oauth.

the problem keep getting error:

the redirect_uri url not supported 

the redirect_uri is:

redirect_uri=localhost%3a3000%2fauth%2ffacebook%2fcallback 

or, simplified:

localhost:3000/auth/facebook/callback 

which url it's supposed being redirected. (api running on localhost:3000)

the client application running on localhost:4000

these configurations in developers.facebook.com:

settings > basic

products > facebook login