http://blogs.msdn.com/b/lukeh/archive/2010/09/05/twitter-oauth-in-f.aspxI have a few F# demos which use the Twitter APIs as simple examples of accessing online data interactively and working with it in F#.&#160;&#160;&#160; Recently, Twitter moved to require OAuth for accessing Twitter APIs on behalf of a user.&#160; Belowen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.msdn.com/b/lukeh/archive/2010/09/05/twitter-oauth-in-f.aspx#10306821Fri, 18 May 2012 15:03:48 GMT91d46819-8472-40ad-a661-2c78acb4018c:10306821Mike<p>OK, I found the bug. The addOAuthHeaderForUser needs to use the baseUri, not the entire uri. You can fix it by changing the first line of the method as shown below:</p> <p>let addAuthHeaderForUser (webRequest : WebRequest) token tokenSecret queryParams = </p> <p> &nbsp; &nbsp;let url = webRequest.RequestUri.ToString().Split(&#39;?&#39;).[0]</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=10306821" width="1" height="1">http://blogs.msdn.com/b/lukeh/archive/2010/09/05/twitter-oauth-in-f.aspx#10305799Wed, 16 May 2012 12:25:34 GMT91d46819-8472-40ad-a661-2c78acb4018c:10305799Mike<p>I&#39;m seeing the same issue. Works when no query parameters are used. 401 errors when I use a query parameter.</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=10305799" width="1" height="1">http://blogs.msdn.com/b/lukeh/archive/2010/09/05/twitter-oauth-in-f.aspx#10114253Tue, 11 Jan 2011 17:22:12 GMT91d46819-8472-40ad-a661-2c78acb4018c:10114253Fahad<p>Luke, I checked your code, oAuth returns a 401 error, I had retrieved the token secret and the other details, it still throws some exception.</p> <p>-Fahad</p> <div style="clear:both;"></div><img src="http://blogs.msdn.com/aggbug.aspx?PostID=10114253" width="1" height="1">