When installing or upgrading Deep Security Manager, the following error message can occur if you are using Microsoft SQL Server as your Deep Security database:

The installer could not establish a secure connection to the database server. Please upgrade or configure your database server to support TLS 1.2 encryption.

The error message appears if the java.security file on the Deep Security Manager includes TLSv1 and TLSv1.1 in the jdk.tls.disabledAlgorithms= setting, which disables early TLS and only allows TLS 1.2. (The java.security file is set this way if you are doing a fresh install of Deep Security Manager 11.1 or higher, where only TLS 1.2 is allowed, or if you are upgrading and previously enforced TLS 1.2.) During the upgrade or installation, the database drivers on the manager try to communicate with the SQL Server using TLS 1.2, and if your SQL Server version does not support TLS 1.2, you'll see this error.

To solve the problem, you must upgrade your SQL Server database to a version that supports TLS 1.2 and then retry the Deep Security Manager installation or upgrade. For a list of SQL Server versions that support TLS 1.2, see this Microsoft article.