The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.

Hello, I executed a simple "edit" command in AML-Studio, It ran at first correctly, but now there is always an exception like:

<SOAP-ENV:Envelope

  xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"

  xmlns:i18n="http://www.aras.com/I18N">

 <SOAP-ENV:Body>

   <SOAP-ENV:Fault>

     <faultcode>999</faultcode>

     <faultstring>HTTP Error</faultstring>

     <faultactor>HttpServerConnection</faultactor>

     <detail>System.Net.WebException: The underlying connection was closed: A connection that was expected to be kept alive was closed by the server.</detail>

    </SOAP-ENV:Fault>

 </SOAP-ENV:Body>

</SOAP-ENV:Envelope>

Does any one know how to remove this problem? Did I somehow locked sth related to this item?