When I first encountered SQL Server Error 40: Could not open a connection to SQL Server, I panicked. The error usually occurs when the SQL Server instance isn’t reachable — maybe due to network issues, incorrect configuration, or a corrupted database file. I spent hours tweaking firewall settings and connection strings, but nothing worked until I used the DRS SQL Database Recovery Tool. It not only helped me fix the issue but also recovered all my crucial MDF and NDF files effortlessly.