I am attempting to write a Windows Desktop App (using WCF) that is a consumer of a web service. The application: Sends a SOAP message to a British Government Server to get an authentication token based on the arugments passed Retrieves a response from that server in the form of a string which contains the authentication token. I have a template of the SOAP message from the British Government, and a WSDL file for the service. What I have tried Add a service reference using the WSDL file. I received the following error: URI formats are not supported. Add a Web Reference using the URL of the service. I received the following error: The request failed with HTTP status 405: Method Not Allowed. Send the SOAP request using a POST. The Call to GetResponse() threw a 500 External Server Error. NOTE: I am using VS 2005 WSDL: <?xml version="1.0" encoding="utf-8"?> <definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:conv="http://www.openuri.org/2002/04/soap/conversation/" xmlns:cw="http://www.openuri.org/2002/04/wsdl/conversation/" xmlns:http="http://schemas.xmlsoap.org/wsdl/http/" xmlns:jms="http://www.openuri.org/2002/04/wsdl/jms/" xmlns:mime="http://schemas.xmlsoap.org/wsdl/mime/" xmlns:s="http://www.w3.org/2001/XMLSchema" xmlns:s1="https://tpvs.hmrc.gov.uk/dpsauthentication" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" targetNamespace="https://tpvs.hmrc.gov.uk/dpsauthentication"> <types> <s:schema elementFormDefault="qualified" targetNamespace="https://tpvs.hmrc.gov.uk/dpsauthentication" xmlns:s="http://www.w3.org/2001/XMLSchema" xmlns="https://tpvs.hmrc.gov.uk/dpsauthentication"> <s:element name="DPSrequestToken"> <s:complexType> <s:sequence> <s:element name="version" type="s:int"/> <s:element name="vendorID" type="s:string" minOccurs="0"/> </s:sequence> </s:complexType> </s:element> <s:element name="DPSrequestTokenResponse"> <s:complexType> <s:sequence> <s:element name="DPSrequestTokenResult" type="s:string" minOccurs="0"/> </s:sequence> </s:complexType> </s:element> </s:schema> </types> <message name="DPSrequestTokenSoapIn"> <part name="parameters" element="s1:DPSrequestToken"/> </message> <message name="DPSrequestTokenSoapOut"> <part name="parameters" element="s1:DPSrequestTokenResponse"/> </message> <portType name="dpsauthenticationSoap"> <operation name="DPSrequestToken"> <input message="s1:DPSrequestTokenSoapIn"/> <output message="s1:DPSrequestTokenSoapOut"/> </operation> </portType> <binding name="dpsauthenticationSoap" type="s1:dpsauthenticationSoap"> <soap:binding style="document" transport="http://schemas.xmlsoap.org/soap/http"/> <operation name="DPSrequestToken"> <soap:operation soapAction="https://tpvs.hmrc.gov.uk/dpsauthentication/DPSrequestToken" style="document"/> <input> <soap:body use="literal"/> </input> <output> <soap:body use="literal"/> </output> </operation> </binding> <service name="dpsauthentication"> <port name="dpsauthenticationSoap" binding="s1:dpsauthenticationSoap"> <soap:address location="https://dps.ws.hmrc.gov.uk/dpsauthentication/service"/> </port> </service> </definitions> SOAP: <!-- v1.1 30/11/2007 --> <!-- 24/10/2011 - minor change to remove duplicated text from <Envelope> element. No impact on validation, therefore not re-versioned. --> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <SOAP-ENV:Header> <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> <wsse:UsernameToken> <wsse:Username>as advised by SDS team</wsse:Username> <wsse:Password>as advised by SDS team</wsse:Password> </wsse:UsernameToken> </wsse:Security> </SOAP-ENV:Header> <SOAP-ENV:Body> <m:DPSrequestToken xmlns:m="https://tpvs.hmrc.gov.uk/dpsauthentication"> <m:version>1</m:version> <m:vendorID>your 4 digit vendorID</m:vendorID> </m:DPSrequestToken> </SOAP-ENV:Body> </SOAP-ENV:Envelope>