Get error with "Unable to verify your credentials"


#1

Url=“https://api.twitter.com/oauth2/token”,
Auth=base64:encode(“2t8SavcTlivWnn7moSBHA:qTqyVjImdzYAMoQwiwSNKU92838wkUkb9tn41T0U”),
wf:header(“Authorization”,"Basic "++Auth),
wf:header(“Content-Type”,“application/x-www-form-urlencoded;charset=UTF-8”),
case httpc:request(post,{Url, [],[“application/x-www-form-urlencoded”],lists:concat([“grant_type=”,“client_credentials”])}, [], []) of

this is my code by erlang,but the twitter reponse me “Unable to verify your credentials”.
i don’t know why ,please reponse me ,thanks