Why is the error showing "SqlException was unhandled by user code"? - asp.net

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: SQL Network Interfaces, error: 50 - Local Database Runtime error occurred. Specified LocalDB instance name is invalid.
I have searched couple of times; but could not solve this problem.

You connection string is wrong so it cannot connect to the SQL server. It is saying the localdb instance name is wrong so it cannot connect.
This thread will help you find out the localdb instances on your computer
SQL Server: How to find all localdb instance names

Related

ASP.NET giving SQL Server errors. Possibly due to no log's configured on SQL Server Express

When I run my ASP.NET application I get this error in my browser:
The application could not connect to the database, please check the connection string in the web.config file and SQL server availability.
Original 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: SQL Network Interfaces, error: 25 - Connection string is not valid)
I checked Event Viewer and found this error:
initerrlog: Could not open error log file ''. Operating system error = 3(The system cannot find the path specified.).
I have SQL Server Express 2019 installed on my laptop so I checked SQL Server Configuration Manager and found the SQL Server process wasn't running so I tried to start it. It failed with this error:
Right now I'm assuming it's all part of the same issue.
I checked the start up parameters expecting to see something like -eC:\Program Files\Microsoft SQL Server\MSSQL15.MSSQLSERVER\MSSQL\Log\ERRORLOG but there was no parameters and when I tried to add the the Add button greyed out.
I'm also unable to connect through SSMS:
TITLE: Connect to Server
Cannot connect to DESKTOP-GK2MRBG.
ADDITIONAL INFORMATION:
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: 2)
For help, click: http://go.microsoft.com/fwlink?>ProdName=Microsoft%20SQL%20Server&EvtSrc=MSSQLServer&EvtID=2&LinkId=20476
The system cannot find the file specified
BUTTONS:
OK
How do I resolve this?

How do I create a database?

I am trying to create a database in my visual studio project, but each time I try and error message pops up; here is the error message i get in my visual studio:
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: SQL Network Interfaces, error: 50 – Local Database Runtime error occurred. The specified LocalDB instance does not exist.)
What should I do?
Often when SQL Server is installed, you can not connect to it using TCP IP.
You will have to enable it.
Here is a link how to: https://learn.microsoft.com/en-us/sql/database-engine/configure-windows/enable-or-disable-a-server-network-protocol?view=sql-server-2017

Can not add a localDB in my website

I installed visual studio2015 then when
I tried to add a database file to my project but every time i tried to do it this message show up
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: SQL Network Interfaces, error: 50 –
Local Database Runtime error occurred. The specified LocalDB instance does not exist.
) (Microsoft SQL Server 2012)

SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified while connecting via asp.net application

While connecting to SQL Server 2012 Express from Asp.Net application, I get the following exception:
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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)
Though, I can connect remotely to the SQL Server but once I published the application to the server where the db resides, I got the above exception.
I tried various approaches shared on net but nothing worked for me. Any suggestions?
There should be a problem in your connection string. check the instance name from Sql Server and then paste that instance name in your connection string.
This error is one of the worst, because you normally don't know what exactly the problem is. Here are some possible solutions:
Check that the server name is correct
Check that the instance name is correct
Check that your server is reachable (seems not to be your problem)
Check that the SQL Browser service is running
Check the firewall rules
Sometimes SQL Error 26 just hides another problem with the connection (f.e. SQL Error 0).

Connection string from SqlException "network-related or instance-specific error?"

Some of my sites are reporting the following error:
System.Data.SqlClient.SqlException: 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)
The site switches connection string dynamically and I suspect the issue is that it is not doing this correctly. If I can extract the server name it is failing to connect to, I can investigate further.
Is there any way to do this in, say, Application_Error in the global.asax?
This can be caused by the SQL Server service stopping running. Open SQL Server Configuration Manager and restart the SQL Server service.

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