We have an issue with our corporate Windows 10 clients checking Certificate Revocation Lists. When accessing websites or logging into apps etc we are seeing the popup message "Revocation Information for the security certificate for this site is not available".
Running a capture I can see that we're getting a 407 proxy authentication required response and the user credentials are not being passed with the request.
For some reason our Windows 7 clients are working successfully so I'm thinking there must be a policy setting wrong somewhere. Has anyone come across this before or know why requests to the CRLs are not working with NTLM authentication?
Update
Doing a bit more digging into the packet capture I can see that the problem seems to be the secondary 407 response from the proxy. After sending -
GET http://g.symcb.com/crls/gtglobal.crl HTTP/1.1 , NTLMSSP_NEGOTIATE
The proxy should respond with -
HTTP/1.1 407 Proxy Authentication Required , NTLMSSP_CHALLENGE
However we're just seeing the connection being reset -
8080 → 58584 [RST] Seq=1176 Win=0 Len=0
