Search code examples
sqlsql-serverwindows-server-2012-r2windows-server-2016

Intermittent connection error after March 2020 security updates


I am facing below error while connecting to the SQL Server on another server from a .NET application.

An exception has been raised that is likely due to a transient failure. If you are connecting to a SQL Azure database consider using SqlAzureExecutionStrategy. The underlying provider failed on Open. A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

SQL Server is running on Windows Server 2016 and the application is on Windows Server 2012.

Everything was fine before those security updates but after updates were installed and servers were restarted, I started getting those errors.

Any suggestions on how to resolve this?


Solution

  • You might want look to look at the following article at Microsoft: Applications experience "forcibly closed" TLS connection errors when connecting SQL Servers in Windows

    I am running into the same issue and I applied the work around, I am still waiting for the results to confirm the solution. It started happening recently in our production environment, as this happens very randomly while connecting to hundreds of servers it is difficult to spot the issue. First we were reviewing network side for lost packets as we work between different data centers. As nothing strange came back from this investigation I stumbled upon the above article.

    Update I applied the workaround, the Group Policy on the local computer, basically followed the instructions of this Group Policy, enabled the policy, copied all cipher suits, removed the TLS_DHE* and applied it. After that restarted the server. The issue has been resolved.