Unable to Connect SQL Server

if you are writing the connection in web.config file. Then you might have missed the PROVIDERNAME="System.Data.SqlClient"

<connectionStrings>
        <add name="NorthConnection" connectionString="server=10.0.3.41;uid=sa;pwd=change_123;database=Northwind" providerName ="System.Data.SqlClient"/>
        
    </connectionStrings>

It might be surface area configuration error or sql service configuration issue. Have a look at this thread for potential reasons and resolutions: Resolving A network-related or instance-specific error occurred while establishing a connection to SQL Server[^]

If needed, See steps for setting up Surface area configuration here..

If this does not resolve your issue, have a look at these thread:
http://forums.asp.net/t/1334649.aspx[^]
SQL SERVER FIX ERROR (provider: Named Pipes [^]
Quite few possible reasons and resolutions are proposed here too.

Check if the Database server is up and running.

Hi Christian Graus,

Thanks for your mail.
Actually when I debugging iam getting an exception "SqlException was unhandled by user code", below its giving

"A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)"

I try to enabled the Named Pipes and TCP/IP things in Sql Server 2005 Network Configuration.
I restarted the Server again and again, still getting the same exception. Do I need to change any settings in my settings. I am using Windows Vista Operating System.

Thanks,

Jhons