Couldn't establish secure ssl connection with "https://********/******?wsdl"

Quote:

https://ProjectNow/CaseCreation?wsdl is the wsdl which i am adding as service reference which is authenticated with Username,Password & Proxy Authenticated.

I have hosted the service in iis with the help of web.config but as the service reference is authenticated one i am not able to connect with it and i get the error as "Couldn't establish secure ssl connection with "https://********/******?wsdl".(checking in the iis error log file)

When i check it through svcutil.exe in visual studio command prompt it shows 407 proxy authentication error.

According to my knowledge web config helps in hosting the service and obtaining metadata from https://ProjectNow/CaseCreation?wsdl so to avoid proxy authentication error i included the following things in my web.config

<system.net>
    <defaultProxy useDefaultCredentials="false">
      <proxy  usesystemdefault="False" proxyaddress ="http://172.16.12.12:8080" bypassonlocal ="True" />
    </defaultProxy>
</system.net>

Quote:

I am passing the above code in my web.config but i have certain password & username for the proxy address

how should i pass the proxy username & password in to the web.config???

I cannot set usedefaultcredentials="true" because the proxy address has different username & password.
How to pass the credentials information for the https://(url) so that i could make a connection it.
Please provide your valuable suggestion.