In certain cases, updating Windows causes TLS 1.0 to be disabled and creates a communication issue between the Solr server and the SQL server. In such cases, the following error occurs in the Manifold logs.
C:\Program Files (x86)\Ektron\SearchX.0\ManifoldCF\logs
The driver could not establish a secure connection to SQL Server by using Secure Sockets Layer (SSL) encryption. Error: "SQL Server did not return a response. The connection has been closed."
This is related to how SSL is configured for Java. More on this here.