The client and server cannot communicate, because they do not possess a common algorithm.

  • Updated

The article describes an error message that can occur accessing an Ektron site after an upgrade and updating servers to TLS 1.2.

This issue is when TLS 1.2 was not available on the CMS/SQL servers. This is a communication issue between the CMS server and SQL server and is most likely unrelated to Ektron in this case.

Make sure that TLS 1.2 is enabled in the registry of both the CMS and SQL servers.

For additional information see the references below.
http://stackoverflow.com/questions/26742054/the-client-and-server-cannot-communicate-because-they-do-not-possess-a-common-a
http://stackoverflow.com/questions/34991417/the-client-and-server-cannot-communicate-because-they-do-not-possess-a-common-a

TLS support for SQL Server
https://blogs.msdn.microsoft.com/sqlreleaseservices/tls-1-2-support-for-sql-server-2008-2008-r2-2012-and-2014/

You may have to apply Windows Updates to one or both servers.