title: WCF - SOAP Action mismatch error while testing with SoapUI
body: <p>How do I fix this?</p>
  
  <pre><code>&gt;  &lt;s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope"
  &gt; xmlns:a="http://www.w3.org/2005/08/addressing"&gt;    &lt;s:Header&gt;
  &gt;       &lt;a:Action s:mustUnderstand="1"&gt;http://www.w3.org/2005/08/addressing/fault&lt;/a:Action&gt;
  &gt; &lt;/s:Header&gt;    &lt;s:Body&gt;
  &gt;       &lt;s:Fault&gt;
  &gt;          &lt;s:Code&gt;
  &gt;             &lt;s:Value&gt;s:Sender&lt;/s:Value&gt;
  &gt;             &lt;s:Subcode&gt;
  &gt;                &lt;s:Value&gt;a:ActionMismatch&lt;/s:Value&gt;
  &gt;             &lt;/s:Subcode&gt;
  &gt;          &lt;/s:Code&gt;
  &gt;          &lt;s:Reason&gt;
  &gt;             &lt;s:Text xml:lang="en-US"&gt;The SOAP action specified on the message, '', does not match the HTTP SOAP Action,
  &gt; 'XX.XXX.WebServices.XXXXService/XXXXService/AuthenticateUser'.&lt;/s:Text&gt;
  &gt;          &lt;/s:Reason&gt;
  &gt;          &lt;s:Detail&gt;
  &gt;             &lt;a:ProblemHeaderQName&gt;a:Action&lt;/a:ProblemHeaderQName&gt;
  &gt;          &lt;/s:Detail&gt;
  &gt;       &lt;/s:Fault&gt;    &lt;/s:Body&gt; &lt;/s:Envelope&gt;
  </code></pre>