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

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

I tried using the local IP address to connect as well as a public one. I've tried:

1. Yes, the site can communicate with the server
2. Named pipes/TCP is enabled.
3. Remote connections are allowed.
4. [Windows Firewall][1] is off
5. Created an exception for port 1433 in Windows Firewall.
6. Enabled everything in SQL Server Configuration Manager.

What else can I do here?

[1]:

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And the simplest solution - check if your slash is back...

I spent about an hour trying to figure out what's wrong with **SERVER/INSTANCENAME** when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a **backslash** (`\`).

The horror, the shame...

Use **SERVER\\\ INSTANCE NAME** .Using double backslash in my project solved my problem.

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" />

Did have the same problem. Spent like 6 hours when had to migrate some servers.
Tried all suggestions available on this topic and others.

**Solution was as simple as server restart!**

After following all the steps mentioned [here](

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), if it still does not connect, try adding the DNS with the IP address in the hosts file in the etc folder. Adding an IP address instead of DNS name in the connection string should be a temporary solution to check if the connection actually works.

I had just installed SQL SERVER 2012 developer. When I was creating my first SSIS package, I received this pipes error when I was trying to create a data connection task in SQL Server 2012 Data Tools in the Connection Manager box. I resolved with the help of the post above.

If choose a named instance and you call your named instance SSQDatabase1 and your pc's name is PCX1. You must enter PCX1\SSQDatabase1 not just SSQDatabase1
or you will receive the named pipes error.

> I tried using the local IP address to connect as well as a public one.
> I've tried:
>
> Yes, the site can communicate with the server Named pipes/TCP is
> enabled. Remote connections are allowed. Windows Firewall is off
> Created an exception for port 1433 in Windows Firewall. Enabled
> everything in SQL Server Configuration Manager.

i ensured and did the above as well and I just want to share that the DOUBLE BACKSLASH

oBuilder.DataSource = "SPECIFICPCNAME\\SQLEXPRESS";

Using a SINGLE BACKSLASH resulted into a build error i.e.: Error 1 Unrecognized escape sequence

I hope this helps the next guy - I've sacrificed dinner, midnight snack and NBA highlights time solving this (shame)

Thanks to [Tamizh venthan]
^_^

in my case, i had a standalone server, i changed the sql server port default port 1433 in configuration manager to some number and restarted the sql serve service to take effect,i was able to connect to the sql server through management studio if i login to the server. but i was not able to connect from my local machine through sql server, i was getting the error:

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) (Microsoft SQL Server, Error: 5)

I checked and verified all the below

-Named pipes/TCP is enabled.
-Remote connections are allowed.
-Windows Firewall is off
-Created an exception for portin Windows Firewall( this was not necessary in my case as the server is in same subnet network).
-Enabled everything in SQL Server Configuration Manager.


then i chnaged back the port number to default 1433 and restarted the sql server service, and the issue got resolved and i am able to connect the sql server from my local management studio.

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.