401 error: "Failed to validate oauth signature and token" message


Hi guys,

I’m trying to fetch a request token for my python application (I’ve no URL callback in app setting) but I’m follow all the steps pointed here https://dev.twitter.com/docs/api/1/post/oauth/request_token and no matter what I do I always get a 401 error with a “Failed to validate oauth signature and token” message.

I’m doing a POST request to https://api.twitter.com/oauth/request_token with this header:

{‘Authorization’: ‘OAuth realm="", oauth_nonce=“80438723”, oauth_timestamp=“1368380749”, oauth_consumer_key="…omitted…", oauth_signature_method=“HMAC-SHA1”, oauth_version=“1.0”, oauth_signature="…omitted…", oauth_callback=“oob”’}

I can even fetch my timeline or my direct messages, but I can not fetch a request token. What I’m doing wrong?