Successfully connected to SQL Server 2008. Enter "exit" when you exit sqlcmd.
The following error occurred while conducting a connection test.
HResult 0x35, Level 16, State 1
Named pipe provider: Unable to open connection to SQL Server [53].
Sqlcmd: Error: Microsoft SQL Server Native Client 10.0: Established with SQL Server, a network-related or instance-specific error occurred. The server could not be found or could not be accessed.
Verify that the instance is correct and that SQL Server is configured to allow remote connections. For more information, see SQL Online books ...
Sqlcmd: Error: Microsoft SQL Server Native Client 10.0: The logon timeout has expired.
Solutions
The client and SQL Server 2008 are on the same server so localhost is absolutely correct, and it is also correct to compare the instance name to the instance name configured when you installed SQL Server.
The connection to the computer name and instance was found to be incorrect.
The command to execute when an error occurs.
SQLCMD-E-S Localhost¥sqlexpress
The correct commands should be as follows.
SQLCMD-E-S Localhost\sqlexpress
After modifying the connector for the computer name and instance, the connection to SQL Server was successful.