Authentication failed because the remote party has closed the transport stream exception when getting a response from webservice

Question

I am calling a third party service and when I ask for a response it throws out an exception that says

\"Authentication failed because the remote part

Answer 1

I had a limitation of using TLS 1.2 only and more than anything else the resource address (URL/address) was local. So above solution didn't work for me. After closely analysing web.config I tried using <bypasslist> for local URLs and miracle happened!

<system.net>
    <defaultProxy>
      <proxy usesystemdefault="false" proxyaddress="<yourproxyaddress>" bypassonlocal="true" />
      <bypasslist>  
        <add address="[a-z]+\.abcd\.net\.au$" />  
      </bypasslist>
    </defaultProxy>
</system.net>

Please note I was already using <proxy> setting for accessing other external URLs so not having this setup was not allowed either. Hope this helps!

Answer 2

I found the answer, It was because the third party webservice we were calling did not support TLS 1.0 they supported 1.1 and 1.2. So I had to change the security protocol.

ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;