title: Invalid SOAP Fault; Unbound prefix used in qualified name
body: <p>I have been trying to fix this error, but I have run out of ideas. I am calling a SOAP webservice with my own WCF service, but I get the following CommunicationException:</p>
  
  <blockquote>
    <p>Server returned an invalid SOAP Fault.  Please see InnerException for more details.</p>
  </blockquote>
  
  <p>And inner (XmlException):</p>
  
  <blockquote>
    <p>Unbound prefix used in qualified name 'soapenv:Server'.</p>
  </blockquote>
  
  <p>So to understand it better I used SOAP UI to see the response I get which is the following:</p>
  
  <pre><code>&lt;SOAP-ENV:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:pbs="REDACTED" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"&gt;
     &lt;SOAP-ENV:Body&gt;
        &lt;SOAP-ENV:Fault&gt;
           &lt;faultcode&gt;soapenv:Server&lt;/faultcode&gt;
           &lt;faultstring&gt;REDACTED&lt;/faultstring&gt;
           &lt;detail&gt;
              REDACTED
           &lt;/detail&gt;
        &lt;/SOAP-ENV:Fault&gt;
     &lt;/SOAP-ENV:Body&gt;
  &lt;/SOAP-ENV:Envelope&gt;
  </code></pre>
  
  <p>As far as I can tell, it has something to do with the faultcode, but I am not entirely sure what it is. I do know I expected a FaultException and not a Communication Exception. There are some information in the detail of the error I would like to react on, but this Exception hides the information from me.</p>
  
  <p>Edit:</p>
  
  <p>This is the request they are receiving on the host (sent from my webservice):</p>
  
  <pre><code>&lt;s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"&gt;
      &lt;s:Body xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" &gt;
          &lt;setREDACTED xmlns="REDACTED" &gt;
              &lt;infotag&gt;info&lt;/infotag&gt;
          &lt;/setREDACTED&gt;
      &lt;/s:Body&gt;
  &lt;/s:Envelope&gt;
  </code></pre>
  
  <p>This it the one i send from SOAPUI:</p>
  
  <pre><code>&lt;soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:pbs="REDACTED" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"&gt;
     &lt;soapenv:Header/&gt;
      &lt;soapenv:Body&gt;
        &lt;pbs:setREDACTED&gt;
           &lt;infotag&gt;info&lt;infotag&gt;
        &lt;/pbs:setREDACTED&gt;
     &lt;/soapenv:Body&gt;
  &lt;/soapenv:Envelope&gt;
  </code></pre>