MS-SQL 2008 R2 Named pipes error 40, SQL server error 53

According to SQL Protocols blog “winerr 1326 means "Logon failure: unknown user name or bad password". When you get this error code, it means a) the client stack is able to reach the target machine, and b) the service account of the client application does not have enough credential to make a NP session to the server. NP is based on SMB (file sharing). The logon failure message represented by winerr 1326 is from SMB layer, not SQL Server. You need to make sure you can make a file sharing to the server machine with the same service account. If you cannot make a file sharing between your server and your client, NP in SQL Server would not success. Try "net use" or "Map Network Drive" to check this. This often happens when server and/or client is not on domain.”

For more details visit :

http://blogs.msdn.com/b/sql_protocols/archive/2007/05/16/named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server-microsoft-sql-server-error-xxx.aspx