Hi Suman,
A few things to check:
If you are not getting a dialog box in MII asking user credentials when you try to connect to the url, then the request is not even getting to the PCo machine. When I have had this issue it was either that the MII proxy bypass settings are not configured correctly in System Configuration, or there was some network router configuration between MII and PCo that was blocking the connection. If you are running MII on a Windows OS, try to remote desktop connect to the MII server and enter the url from IE on that server to see if it will return a wsdl.
Regards,
Steve