How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

Question

I can\'t seem to connect to my database from a site. I get this error:

Named Pipes Provider, error: 40 - Could not open a connection to SQL Server

Answer 1

Enable TCP/Ip , Piped Protocol by going to Computer Management ->SQL and Services, ensure the Service is On. Enbale the port on the Firewall. Try to login through Command Prompt -> as Admin; last the User Name should be (local)\SQLEXPRESS. Hope this helps.

Answer 2

For me it was a Firewall issue.

First you have to add the port (such as 1444 and maybe 1434) but also

C:\Program Files (x86)\Microsoft SQL Server\90\Shared\sqlbrowser.exe

and

%ProgramFiles%\Microsoft SQL Server\MSSQL12.SQLEXPRESS\MSSQL\Binn\SQLAGENT.EXE

The second time I got this issue is when I came back to the firewall, the paths were not correct and I needed to update form 12 to 13! Simply clicking on browse in the Programs and Services tab helped to realise this.

Finally, try running the command

EXEC xp_readerrorlog 0,1,"could not register the Service Principal Name",Null

For me, it returned the error reason

Answer 3

Thanks to Damian...

TCP/IP Named Pipes ... both enabled

Web Config....(for localhost)

<add name="FooData" connectionString="Data Source=localhost\InstanceName;Initial Catalog=DatabaseName;Integrated Security=True;" providerName="System.Data.SqlClient" />

Answer 4

I have suggested below steps to resolve your issue How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'

1. Check for working fine SQL Server Services services or not.
2. Also check for working in good condition SQL Server (MSSQLSERVER).
3. Also check for working fine SQL Server Browser.
4. Delete all earlier Aliases, now create new aliases as per your requirements.
5. Now check for working of SQL Server Default Port 1433
6. Next click on Client Protocols in instance, then click on TCP/IP, now click on mouse right click, open the Property, here you can make assure your working fine your default port SQL 1433.
7. Open your SQL Server Management Studio, then right click, click on "Property" option and then click on Connections tab, then finally tick for Allow remote Connections to this server.
8. Check for right working or your Ping IP Host.

Answer 5

I have one more solution, I think. I recently had changed my computer name so, after I couldn't connect still after trying all above methods. I changed the Server name.. Server name => (browse for more) => under database engine, a new server was found same as computers new name. This worked, and life is good again.

Answer 6

Very simple solution

use (local)\InstanceName that's it. it worked for me.