title: 'a:Action' must be understood but cannot be handled and RequestSecurityToken problem on an ONVIF Camera
body: <p>I'm trying to establish a communication with an ONVIF camera, and I'm getting some strange errors that I can't fully comprehend due to my lack of experience with Web Services, ONVIF and C#. I'm on .NET 4.0 and using Visual Studios 2010</p>
  
  <pre><code> EndpointAddress endPointAddress = new EndpointAddress("http://192.168.3.246:80/onvif/device_service");  
  WSHttpBinding bind = new WSHttpBinding();  
  bind.Security.Mode = SecurityMode.Message;  
  bind.Security.Message.ClientCredentialType = MessageCredentialType.UserName;
  DeviceClient temp = new DeviceClient(bind, endPointAddress);  
  temp.ClientCredentials.UserName.UserName = myusername;  
  temp.ClientCredentials.UserName.Password = mypassword;  
  SystemDateTime s = temp.GetSystemDateAndTime();
  </code></pre>
  
  <p>This lead to a crash with the erorr "The data in element 'a:Action' must be understood but cannot be handled". I've tried to manually catch the request and to execute it with the <code>"s:mustUnderstand="1</code>" flags turned off, but I then get an "Method 't:<code>RequestSecurityToken</code>' not implemented: method name or namespace not recognized" error.</p>
  
  <p>Is my <code>ONVIF</code> camera bugged, or am I doing something wrong ? I've been trying various things since 3 days to try to connect to that camera beyond simple, non-secured informations like <code>GetSystemDateAndTime</code>() and <code>GetDeviceInformation</code>(), but I'm stuck. </p>