The TCP/IP connection to the host localhost, port 1433 has failed. Error: "Connection refused: connect. Verify the connection properties, check that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port, and that no firewall is blocking TCP connections to the port.
Verifique se a configuração do SQL Server permite aceitar conexões TCP/IP. Habilite o TCP/IP e reinicie o SQL Server. Em seguida, teste seu código novamente.
