Following error occurs connecting to SQL Server 2008 using ADO connection type:
"Test connection failed because of an error in initializing provider. [DBNETLIN][ConnectionOpen (Invalid Instance()).]Invalid connection."
Named instance
If SQL Server instance is a named instance sever, then in Server Name field, enter server name and instance name as such:
servername\instancename
Also try adding port number to the same field as such:
servername\instancename,1433
