I am trying to setup an application on my local machine for some dev/troubleshooting efforts. This site currently runs on a Windows 2003 R2 Standard with IIS 6 and connects through a COM+ proxy to another server with the identical OS build. This setup works fine, along with most any developers who are using their machines (WinXP) as the IIS standin pointing to the dev app server. I am running Windows 7 and IIS 7.5 on my box. After setting up the web application and installing the COM+ proxies, I am getting the below error when trying to make calls to a certain component. Microsoft VBScript runtime error '800a01ce' The remote server machine does not exist or is unavailable: 'GenericFunction' I know the application server that I am proxying to works, as many others are using it. I've ran a netcap to look at the traffic when this connection happens and I saw this entry which looks to be the reason I can't connect. DCERPC Bind_ack: call_id: 63, NTLMSSP_CHALLENGE Unknown result (3), reason: Abstract syntax not supported I've been searching all over for this, but I can't seem to figure out what is causing the connection failure. Any help would be appreciated.

Good morning, I have a very similar Problem. A Winhttp Application is run over a squid proxy with NTLM activated. on XP Pcs i see a correct NTLM "handshake" up to NTLMSSP_CHALLENGE with accouring response. On Windows 7 PCs i see the same Trace with the acception, that the TCP connection is closed on receiving the NTLMSSP_CHALLENGE and the response is send on a new TCP connection. THe problem seems now that theNTLMSSP_CHALLENGE was send with UNICODE=1, the response is sent therefore in UNICODE (UTF16), but the Proxy lost the information that UNICODE was requested) therefore the Response is not accepted. I have seen in the MSDN that the WinHTTP Api has changed a bit with Vista SP2, but didn't found a clue what could cause this different behaviour. Has anybody solved it?. kind regards Wolfgang

I got now more Details: Same code - Windows XP: WinHttpReceiveResponse fails, and GetLastError()=ERROR_WINHTTP_RESEND_REQUEST Windows 7: WinHttpReceiveResponse does not fail, and the code calls WinHttpQueryHeaders get Status 407, call WinHttpQueryAuthSchemes and call WinHttpSetCredentials. Somewhere there the TCP connection is closed a new one ist established. First question: Why the difference in WinHttpReceiveResponse second Question: I found no documentation that the TCP connection should be closed on this api calls. kind regards Wolfgang