I wanted to configure a separate SQL server to do a vCenter migration and I was getting errors to connect to the DB server, I was able to fix this issue after doing some changes in the SQL server. Here, I thought to post the steps that I took to resolve the issue. I believe this post will help others who involved with the configuration and resolve these type of issues in the middle of their configuration without wasting more time on this.
I have installed a fresh SQL 2008 R2 server with the custom SQL instance (SQL Express instance name is not the default one). Installed the relevant SQL Native client and tried to connect to the DB Server. It was throwing the below error message