Hi all, I use C# to use contact api to fetch contacts, I follow guide of contact api and some articles of this forum to buid some sucessuflly steps
1. Request Token : success
2.Request Access : success ( this step I obtain access token, access token secret and guid of user)
3. Build url and sign request url under "HMAC-SHA1" to make a request fetch contact , my url signed as following:

http://social.yahooapis.com/v1/user/LULAPA...orization=OAuth

But this step always get response 'Please provide valid credentials. OAuth oauth_problem="token_rejected", realm="yahooapis.com"' ( in browser is code 401 : Authorization Required).
There 's any body suggest about the way to pass Authorization for this url?
Thank you very much!