The SQL Server Error 40 can be either Named Pipes connections or TCP/IP connections related errors. we look at what may be causes to these. How do you fix the Error: 40 problem? Simply open the network port. Starting on SQL Server, open Windows Firewall with Advanced Security. Click on the. Microsoft SQL Server Error 40 – Root Cause · Server is probably not started and shutdown. · SQL Server Service is down. · SQL Server Instance is.
How: Error 40 sql server
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Error 40 sql server - your idea
In this SQL Server tutorial, we will learn how to resolve the “provider: named pipes provider, error: 40 – could not open a connection to sql server” error. So, in this tutorial, we will discuss the root cause of this error and will also discuss how to solve the error, could not open a connection to sql server error 40.
Could not open a connection to sql server
Recently, I have encountered this error while connecting to the Database Engine using SQL Server Management Studios. The complete error message is shown in the image below.
Cannot connect to
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. error 40 – could not open a connection to sql server.
Let’s first discuss some of the main reasons behind this error message.
- We might be using wrong server name to connect due which the failure has occured.
- The SQL Server Service is not running properly or it might have wrong default settings.
- The SQL Server do not have permission to allow an remote connection.
- The host machine might have wrong firewall settings.
Don’t worry if you don’t know how to resolve these issues to overcome this error. Here are some of the steps that we can follow to overcome these issues.
Fix 1: Use Correct Server Name
Many times the main reason behind this error is the use of the wrong server name while connecting. To connect to the Database Engine in the SQL Server, we need to provide some login details such as username, password, and server name.
Now, it is important to use the correct server name. By default, the server name is in the following format – “ComputerName\InstanceName“.
In this format, the ComputerName is the name of the machine or computer. Now, if you are using Windows 10 OS, you can get this name by opening the About page in your System settings. The example for this is shown below.
Next, in the server name is InstanceName which is the name of your SQL Server instance. Now, to get the instance name, we need to open the Services setting in our system.
And from the list, we have to find the SQL Server Service. The instance name is there in the brackets of the service name. The example is demonstrated below.
In our case, the name of the instance is SQLEXPRESS. So, the server name will be similar to “DESKTOP-XXXX\SQLEXPRESS“.
Fix 2: SQL Server should be up and running
The second root cause for this error can be because your SQL Server instance is not running. Now, to check wheater the instance is running or not. First, we need to open the “SQL Server Configuration Manager“.
In SQL Server Configuration Manager, first, click on SQL Server Services then, a list of services will appear on the right pane. From the list check the state of the “SQL Server” service. And we can also right-click the service and click on “Start” to start the service.
Next, we should also confirm whether the SQL Server Browser is running or not in the same way.
Fix 3: Enable TCP/IP in SQL Server Configuration
Whenever multiple SQL Server instances are connected across a network, they all use TCP/IP for communication. So, to resolve this error, we have to confirm whether the TCP/IP is enabled or not. For this, again we will use the “SQL Server Configuration Manager“.
In SQL Server Configuration Manager, first, expand the “SQL Native Client Configuration” then, click on “Client Protocols“. A list of protocols will appear on the right pane. From the list check the state of TCP\IP. And we can also right-click it and click on the “Enable” option to enable it.
Next, we can also confirm whether TCP\IP is working on the default ports or not. For this, first, right-click TCP\IP and click on Properties. Next, from the General category, we can confirm whether the default port is or not.
Fix 4: Allow Remote Connections
Other than enabling the TCP\IP, we have to enable the remote connection settings from the SQL Server properties. For this task, we can use SQL Server Management Studio. Here are steps to enable the property using SQL Server Management Studio.
- From the Object Explorer, right-click on the server name and click on “Properties” option.
- Next, open the Connection properties section and tick mark the “Allow remote connections to this server” option. In the end, clcik on “OK” to save changes.
Fix 5: Allow SQL Server in Firewall Settings
The Windows Firewall is quite effective at safeguarding the operating system from various dangerous threats. By default, the firewall prevents numerous ports and services from running.
To overcome this issue, we can add a firewall exception for TCP/IP ports or . So, the SQL Server can run without any issue.
The steps to add the exception in the Windows firewall are as follows.
- First, search for “Windows Defender Firewall with Advanced Security” in our start and open it.
- Next, from the left pane click on “Inbound Rules” and then, click on “New Rule“. It will open a new “Inbound Rule Wizard” window.
- In the new window, first, select “Port” and then click on “Next“. After this, select the “TCP” option and specify the port number as .
- Next, we need to select the “Allow the connection” option and click on the “Next” button.
- Next on the Profile page, tick marks the options as per your requirements and again click on the “Next” option.
- On the last Name page, specify the name and description for the exception and click on the “Finish” button.
With this, we have added the new firewall which will allow having a remote connection in SQL Server.
By following all the given solutions, we can resolve the error and we can easily connect to the SQL Server instance.
So, in this tutorial, we have learned how to resolve the “provider: named pipes provider, error: 40 – could not open a connection to sql server” error. In this, we have discussed the root cause of this error and also the possible solution for it.
You may also like to read the following SQL Server tutorials.
I hope this will help to fix the below errors:
- named pipes provider, error: 40 – could not open a connection to sql server
- a network-related or instance-specific error in sql server error: 40
- a network-related or instance-specific error in sql server
- named pipes provider: could not open a connection to sql server (53)
- could not open a connection to sql server error 40
- error 40 – could not open a connection to sql server
- error 40 could not open a connection to sql server error 53
Bijay Kumar Sahoo
After working for more than 15 years in the Software field, especially in Microsoft technologies, I have decided to share my expert knowledge of SQL Server. Check out all the SQL Server and related database tutorials I have shared here. Most of the readers are from countries like the United States of America, the United Kingdom, New Zealand, Australia, Canada, etc. I am also a Microsoft MVP. Check out more here.
SQL Server Error A network-related or instance-specific error occurred while establishing a connection to SQL Server.
Today, a user has raised a request to fix an error (Microsoft SQL Server Error 40 Could not open a connection to SQL Server or Microsoft SQL Server, Error 2) he was getting while establishing the database connection. Sometimes you might get this error with text ( provider: Named Pipes Provider, error: 40 Could not open a connection to SQL Server).
The error details are given below.
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 – Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)
Below is the screenshot of above Microsoft SQL Server error
Sometimes, we get same error under below error text.
An error has occurred while establishing a connection to the server. When connecting to SQL Server, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 Could not open a connection to SQL Server) (.Net SqlClient Data Provider)
Microsoft SQL Server Error 40 Root Cause
We get SQL error 40 because SQL Server did not respond to the client request. This issue occurs due to multiple reasons. I have given all those possible reasons behind Microsoft SQL Server error 40 in below points.
- Server is probably not started and shutdown.
- SQL Server Service is down.
- SQL Server Instance is not accessible due to firewall or any reason.
- Telnet port or port no on which SQL Server is running. These ports might be blocked.
- TCP/IP or Named Pipes protocol is disabled in SQL Server Configuration Manager.
- Remote Connection is disabled for this SQL Server Instance.
- SQL Server browser service is stopped.
- Wrong SQL Server Instance name while establishing database connection
We need to check and validate multiple factors to rectify Microsoft SQL Server error Check all factors given in below step by step points to fix all possibilities for this error.
- Make sure that database server is up and running fine.
- Make sure SQL Server services are running fine and its accessible.
- Check firewall details. Firewall should open between your client machine and database server.
- Port and should be enabled. Telnet both ports to make sure ports are open.
- Make sure to enable TCP/IP and Named Pipes protocols. Launch SQL Server Configuration Manager. Expand SQL Server Network Configuration from left side pane and click on Protocols for MSSQLSERVER. MSSQLSERVER is SQL Server Instance name. Now you will see all protocols in to right side pane. Right click on given protocols and select Enable button to enable both protocols.
- Remote connection must be enabled to connect to databases remotely. Connect to SQL Server Instance in SSMS. Right click on SQL Server instance name in SSMS and choose Properties. You will get Server properties window. Click on Connections from left side pane and tick the check box on Allow remote connections to this server option from right side pane.
- SQL browser service should not be stopped if your security policy allows it. If you have disabled this service to apply hardening then make sure to pass port no along with SQL Server instance name while making database connection.
- Sometimes, we enter wrong server details. Make sure to enter correct SQL Server instance name while making database connection.
Here, I have given different solutions to fix sql error 40 in SQL Server. I hope you like this article. Please follow our Facebook and Twitter handle to get latest updates.
Manvendra Deo Singh
I am working as a Technical Architect in one of the top IT consulting firm. I have expertise on all versions of SQL Server since SQL Server I have lead multiple SQL Server projects like consolidation, upgrades, migrations, HA & DR. I love to share my knowledge. You can contact me on my social accounts for any consulting work.
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Fix Error A network-related or instance-specific error occurred while establishing a connection to SQL Server.
Today, a user has raised a request to fix an error that he was getting while establishing the database connection. The error details are given below. 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 – Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2)
Manvendra Deo Singh
SQL server error 40 Different ways to fix it
The error SQL server error 40 occurs while we try to connect to the SQL Server.
Here at Bobcares, we have seen several such SQL related issues as part of our Server Management Services for web hosts and online service providers.
Today we’ll take a look at the cause for this error and see how to fix it.
What causes the error SQL server error 40 to occur
Here are the different causes of this error to occur.
- Connection to the server instance fails
- Using wrong default settings
- SQL Server doesnt have enough permissions to allow the remote connection.
- The problem in firewall settings
How we fix SQL server error 40
Now lets take a look at the various fixes to resolve this error.
1. If the SQL Server instance is not running.
Now go to Services option and click on SQL Server installed in your system. If its status is not Started, then start it by clicking on the START option.
2. Enabling TCP/IP
Ensure that the TCP/IP is enabled on the server. In case, if it is not enabled then follow the below steps to enable it.
First, click on the Configuration Manager of SQL Server.
Check if the TCP/IP port status is enabled or not. If not, then you would need to enable it and then click on the status to change the port properties.
Now enter the Default Port number and click on the OK button.
3. Allow Remote Connections enabled under Connections in SQL Server Properties.
Below are the steps to enable it.
First, open the SQL Management Studio and then right-click on the Server Name.
Now, click on the Server Properties. Then under the Connections Options, check the box of ‘Allow remote connections to this server’ and then click on the OK button.
4. Allow SQL Server in Firewall Settings:
Add a Windows Firewall exception on the server for SQL TCP ports and , so that SQL Server will run. Here are the steps to do the same.
First, go to Control Panel then System and Security, or directly search it on your system search as Windows Firewall.
Now, click on the Firewall. Here you can see the Action tab as Allow for Firewall. You can change it through SQL Server Properties to allow or block.
5. Verify whether the SQL server is reachable using ping
Ensure that you are able to ping the physical server where SQL Server is installed from the client machine. If you are not able to then you can try to connect to the SQL Server using an IP Address (for default instance) or IP Address\Instance Name for a named instance.
6. Verify whether SQL Server Browser service is running or not
It is important for the SQL Server Browser service to be running well. So make sure that it is running well.
However, if you have installed a SQL Server named instance and not configured a specific TCP/IP port then the incoming requests will be listening on a dynamic port.
In order to resolve this, you would need to have the SQL SQL Server Browser service enabled and running. Moreover, you can check the status of browser service using either SQL Server Configuration Manager or the SC command as below:
sc query sqlbrowser
Also, make sure to add an exception for sprers.eu in the firewall.
7. Confirm that you are using the right SQL Server instance name
Ensure that you are using the right instance name. Whenever you connect to a default instance, machinename is the best representative for the instance name. However, when you connect to a named instance such as sqlexpress, you would need to specify the instancename as machinename\instancename where you enter the SQL Server instance name for instancename.
8. Verify the port number that SQL Server is using
In order to verify the port number, locally connect to the SQL Server and check the error log for the port entry. You can verify this in SSMS. Below are the steps for the same.
Access the Management in SSMS
Now, go to SQL Server Logs and select the Current log.
Scroll down to the bottom which will be the first entry in the error log and look for entries to check whether Named Pipes and TCP/IP are enabled and the port used for TCP/IP.
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In short, this error occurs while we try to connect to the SQL Server. Today, we saw how to fix this SQL error.
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How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?
TL;DR; Your SQL Server instance is using dynamic ports which is not working. Force SQL Server to use static port #
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 # 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 shown below:
Solution # 3: Force your named instance to use port # 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 # already. Same port number can't be uses by two different Windows services.
Mark field to blank and field to
Change the port number in your connection string as shown below:
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.
answered Apr 13, at
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Fix SQL Server Management Studio Error 40