Consider the following scenario. You have a web browser installed on a computer running a Windows-based operating system. You try to use the web browser to view a website over a secure SSL/HTTPS connection. In this configuration, you are unable to connect to the website over SSL/HTTPS. When the problem occurs users may see error messages similar to the following, depending on the version of their web browser:
Cannot find server or DNS Error
There is a problem with this website's security certificate. Security certificate problems may indicate an attempt to fool you or intercept any data you send to the server
Internet Explorer Cannot Display the Webpage
When the problem occurs, you may be able to view the same website over a standard HTTP connection (which doesn't use SSL), and you may be able to view other websites over an SSL/HTTPS connection.
The problem occurs because the Microsoft Knowledge Base article KB2661254 was installed on the client machine, and the website the client is trying to browse to over SSL has an RSA security certificate that uses cryptographic keys that are less than 1024 bits in length. For more information regarding the security impact associated with the changes made by KB2661254, please see the Microsoft Security Advisory 2661254.
If you are the website Administrator and the website is running on Microsoft Internet Information Services (IIS), please see the More Information section below for information on attaining and installing SSL Certificates.