Error: 26 - Error Locating Server/Instance Specified after hosting to a web server - Stack Overflow
Fixed] Error 26: Error Locating Server/Instance Specified in SQL Server 2008 - Codingvila
Connect to SQL Server using port number
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL
SQL Server 2008 R2 stop working over local network (error 26) - Stack Overflow
Enable Remote Connection on SQL Server 2008 Express – Sharing my experience