如何修复错误“命名管道提供程序，错误 40 - 无法打开与“SQL 服务器”的连接？

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

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 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?

Answer 1

Solving this problem is very easy:

1. Go to control panel.
2. search for services.
3. Open Local services window from your search results
4. Restart your MSSQLSERVER service.

Screenshot of the steps:

Answer 2

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...

Answer 3

It's a three step process really after installing SQL Server:

1. Enable Named Pipes SQL Config Manager --> SQL Server Network Consif --> Protocols --> Named Pipes --> Right-click --> Restart

2. Restart the server SQL Config Manager --> SQL Server Services --> SQL Server (SQLEXPRESS) --> Right-click --> Restart

3. Use proper server and instance names (both are needed!) Typically this would be .\\SQLEXPRESS , for example see the screenshot from QueryExpress connection dialog.

There you have it.

Answer 4

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.

Answer 5

A thread on MSDN Social, Re: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server , has a pretty decent list of possible issues that are related to your error. You may want to see if any of them could be what you're experiencing.

• Incorrect connection string, such as using SqlExpress
• Named Pipes(NP) was not enabled on the SQL instance
• Remote connection was not enabled
• Server not started, or point to not a real server in your connection string
• Other reasons such as incorrect security context
• try basic connectivity tests between the two machines you are working on

Answer 6

我刚刚在 Sql Server 配置管理器中启用了 TCP/IP、VIA、命名管道，我的问题得到了解决，请参阅此了解更多信息解决命名管道错误 40

Answer 7

使用SERVER\\\\ INSTANCE NAME 。在我的项目中使用双反斜杠解决了我的问题。

Answer 8

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 9

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!

Answer 10

TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port # 1433.

Complete Details : First of all this problem is more likely if you've a mix of default and named instance or named instances only(which was my case).

Key concept : Each instance of Microsoft SQL Server installed on a computer uses a different port to listen for incoming connection requests. Default instance of SQL Server uses port # 1433. As you install named instances then they will start using dynamic ports which is decided at the time of start-up of Windows service corresponding to named SQL Server instance.

My code was failing (with error code 40) to connect to the only named SQL Server instance that I had on my VM. You can try below possible solutions:

Solution # 1 : Client code trying to connect to SQL Server instance takes help from SQL Server browser service to figure out port number at which your named instance is listening for incoming connections. Make sure SQL browser service is running on your computer.

Solution # 2 : Check the port # (in yellow color) your named SQL Server instance is using from SQL Server configuration manager as shown in the snapshot below:

Use that port number explicitly in your connection string or with sqlcmd shown below:

sqlcmd -s mymachinename,11380 -i deleteDB.sql -o SQLDelete.txt

Solution # 3 : Force your named instance to use port # 1433 which is used by default instance. Remember this will work only if you don't have any default SQL Server instance on your computer as the default SQL Server instance would be using using port # 1433 already. Same port number can't be uses by two different Windows services.

Mark TCP Dynamic ports field to blank and TCP Port field to 1433.

Change the port number in your connection string as shown below:

sqlcmd -s mymachinename\instanceName -i deleteDB.sql -o SQLDelete.txt

OR

sqlcmd -s mymachinename,1433 -i deleteDB.sql -o SQLDelete.txt

Note : Every change in TCP/IP settings requires corresponding Windows service restart.

Interestingly enough after resolving the error when I went back to dynamic port setting to reproduce the same error then it didn't happen. Not sure why.

Please read below interesting threads to know more about dynamic ports of SQL Server:

How to configure SQL Server Port on multiple instances?

When is a Dynamic Port “dynamic”?

When to use a TCP dynamic port and when TCP Port?

I got leads to solution of my problem from this blog.

Answer 11

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.

Answer 12

I had the same problem. I use the MSSQL Server Management Studio 2017 and solved this problem using these steps:

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. Restart SQL Server (MSSQLSERVER)

and fixed it.

Answer 13

You will find most likely your DB name is not correct, you will see the server name in VS like "DESKTOP-0I14BKI" but if you open up SSMS you will see DESKTOP-0I14BKI\\SQLBLAHBLAH , simply add " \\SQLBLAHBLAH " (instance name) to your "server name" in VS connection properties.

You will see :

To Fix:

Answer 14

Very simple solution

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

Answer 15

Try the following steps:

1. Open Services window (open "run box" and type services.msc).

2. Looking for SQL services (with SQL prefix).

3. Start them (if cannot start. Goto step 4).

4. Right_click to each service -> Properties -> Change to tab "Log on"-> choise log on as "Local ..." -> 0K. Then start SQL services again.

Try Open SQL and connect database.

Answer 16

In my case, I opened SQL Server Management Studio and searched for SQLEXPRESS in my Database engine. It had two instances and I selected the correct one.

Answer 17

If you are working with Asp.net core and using appsettings.json than write server as localhost and after write sql instance name for enabled named pipe like this

  "ConnectionString": {
    "dewDB": "server=localhost\\dewelopersql;database=dewdb;User ID=sa;password=XXXXX",
  },

Answer 18

If you tried restarting the MSSQLSERVER service, and it did not work, this might be a solution:

If you are using SQLExpress, your server name should be as the following ComputerName\\SQLExpress. However, for SQLDeveloper, you do not have to right SQLDeveloper after your ComputerName.

Answer 19

After following all the steps mentioned here , 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.

Answer 20

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 ie: 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] ^_^

Answer 21

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 22

Open SQL Server Configuration Manager

1. Select SQL Server Services from right.
2. Find your server from right and go to its properties (with right click)
3. Change log on method to Local System.

Answer 23

I had the same problem and solved the problem by disabling my firewall(ESET).

The first step to solve this problem should be to try pinging your own computer from another computer. If you have firewall on, you may not be able to ping yourself. I tried pinging my own pc, then ping was failed(didnt get response from the server)

Answer 24

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 25

I was trying to add a new connection in VS2015. None of the suggestions here worked. Suspecting some sort of a bug in the wizard, especially since SSMS was able to connect just fine, I decided to try and trick it. It worked!

1. Instead of adding the connection, use "Create new SQL Server Database". Enter your server name and a random name for the new DB, eg "test".

2. Assuming this succeeds, open Server Explorer in VS, locate the connection in Data Connections, right-click it and select Modify Connection.

3. Change "test" (from step 1) to the name of the existing database you want to connect to. Click "Test Connection". This time it should work!

4. Delete the temporary database you created in step 1.

Answer 26

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 27

在我意识到我的错误之前，我在这个问题上挣扎了很长时间 - 我在连接字符串中使用了逗号而不是分号

Answer 28

I had this issue but none of the suggestions above fixed it.

I was seeing this issue when I deployed my website to IIS. The fix was to go into advanced settings against the default app pool and change the identity property from the default to Administrator.

Answer 29

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 30

I tried pretty much everything on this page but I had some underlying issues which were actually what needed to be resolved. I was unable to do certain things like open SQL Server Configuration Manager, which ended up being corrupt/missing WMI provider files.

There are lots of tedious ways to resolve this issues according to what I've read, but the tool from tweaking.com was able to remove and replace/repair my WMI (Windows Management Instrumentation) Provider files.

I used to do computer repair and overall the tweaking.com tool really impressed me, and it was suggested from one of the WMI error forum pages I went to.

After I fixed this issue I was able to connect to my SQL db, both locally and remotely.

Hope this helps someone.

Answer 31

在您的服务器上打开端口号 1433 以进行 sql 远程连接

Answer 32

I was getting this error on linked server which has gone offline. It was inside of a sql query, which was inside a dll, which was in another project, and in another language (VB). Copy your query into sql studio manager and run directly from there to see if this is your problem as well.

Answer 33

I had a different version of this issue when trying to connect Power BI desktop to a local developer instance of SQL Server 2019. I was using:

localhost:<port>

Changing it to:

hostname\servername

solved it for me. Possibly complicated by the fact I have 2 SQL Server installations on my machine on different ports.