Several applications, mostly in our online environment, are experiencing the following error:

System.ServiceModel.CommunicationException: An error occurred while making the HTTP request to This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case. This could also be caused by a mismatch of the security binding between the client and the server. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host"

The cause is related to TLS 1.1 Disabled in our online environments, which was announce in November 2019. 

Those who are experiening the errors are still running Windows Server 2008. 

Windows Server 2008 R2 had an update that supported TLS 1.2, but both Windows Server 2008 and 2008 R2 is end of life on January 14, 2020, so we recommend partners upgrade their servers as soon as possible.

Best regards!

RE: System.ServiceModel.CommunicationEx­ception

We just figured out this error at a new online customer with a custom app. Unfortunately the customer can not update the Server OS becouse of there ERP solution.

Finaly we was able to enable TLS1.2 on Win Server 2008 R2 like this:

Or in german:


Av: Georg Diczig 14. jan 2020

RE: System.ServiceModel.CommunicationEx­ception

We have discovered Windows Server 2012 R2 to be the most common culprit, but there could be other server versions affected. 

The heart of the problems is misconfigured cryptographic ciphers disabled on the servers hosting the partner applications.

First, we would like to give thanks to David Hollegien of All-CRM for sharing a complete log that gave us something to work with.

Secondly, we would like to thank Frode Svensson of Business Analyze AS for providing sharing details that helped solve the problem on there on their web servers, and link to an article about how to setup Microsoft Windows or IIS for SSL Perfect Forward Secrecy and TLS 1.2

The easy fix: on your web servers hosting your applications, download the free tool IIS Crypto, and on the Cipher Suites tab, enable the following ciphers:


Hope this helps!


Av: Tony Yates 21. jan 2020

RE: System.ServiceModel.CommunicationEx­ception

And use SSLLabs to check your configuration - having TLS 1.0 and 1.1 enabled will degrade your server to a B from January 2020

Av: Margrethe Romnes 21. jan 2020