Linked Server error

Dear All,

When I tried to create a Linked Server I get the following error message would you please let me know what would cause the issue please?

Named Pipes Provider: Could not open a connection to SQL Server [53].
OLE DB provider "SQLNCLI" for linked server "Servername" returned message "Login timeout
expired".
OLE DB provider "SQLNCLI" for linked server "Servername" returned message "An error has
occurred while establishing a connection to the server. When connecting to SQL Server 2005,
this failure may be caused by the fact that under the default settings SQL Server does not
allow remote connections.". (.Net SqlClient Data Provider)

Thank you in advance!