title: Unauthorized when attempting to post tweet api v1 (C#)
body: <p>Morning all,</p>
  <p>I've not posted on SO for quite some time, but I need to ask the question, I’ve spent a day and a half trying to get this to work - it’s super frustrating considering I managed to implement v2 with posting a tweet in 2 - 3 hours but because I need the media endpoint (does not exist in v2), I rebuilt my flow into v1 to upload media.</p>
  <p>Ok, so my app allows the user to authenticate with twitter and tweet/upload media. I’m using (I think) the 3-legged oauth flow.</p>
  <p>Currently, the flow is :</p>
  <ul>
  <li><a href="https://api.twitter.com/oauth/request_token" rel="nofollow noreferrer">https://api.twitter.com/oauth/request_token</a> - 200 status code and I
  confirm the callback URL</li>
  <li>I use the access token from step 1, and then call/redirect
  <a href="https://api.twitter.com/oauth/authorize?oauth_token=%7BaccessToken%7D" rel="nofollow noreferrer">https://api.twitter.com/oauth/authorize?oauth_token={accessToken}</a>
  this obviously redirects to my endpoint.</li>
  <li>I extract the oauthToken and oauthVerifier and call:
  <a href="https://api.twitter.com/oauth/access_token" rel="nofollow noreferrer">https://api.twitter.com/oauth/access_token</a>, this returns an
  oauthToken and oauthTokenSecret, I store the values.</li>
  </ul>
  <p>All of the above conforms to what is in the docs, but when I use the stored values from step 3 to post a tweet I get unauthorized.</p>
  <p>The signing logic works because it’s what’s used in “Request access token” - with a couple of changes.</p>
  <p>I'm learning more towards a flow issue due to trying various nuget packages(tweetinvi in particular) and I get exceptions in those too.</p>
  <p>Any help is greatly appreciated.</p>