error: 50 - Local Database Runtime error occurred, but if I publish the project, it works normally

Question

Server Error in '/' Application.

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. Cannot create an automatic instance. See the Windows Application event log for error details. )

I'm not sure, after I created a network service the problem occurs:

USE [master];
CREATE LOGIN [NT AUTHORITY\NETWORK SERVICE] FROM WINDOWS;
EXEC sp_addsrvrolemember N'NT AUTHORITY\NETWORK SERVICE', SYSADMIN;

I have tried to use different connection string to test my connection

Data Source=(localdb)\mssqllocaldb
//publishing and compiling error

But if I build & publish templating direct to local IP for the connection string, the error does not appear...

Data Source=192.168.100.233
//compiling error

I have no idea about this problem..

Answer 1

You may have a firewall issue 1433 or you did not setup MixedMode Authentication , you need to open the ports from services.msc and look for sql server services and under TCP and named pipes

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To begin - there are 4 issues that could be causing the common LocalDb SqlExpress Sql Server connectivity errors SQL Network Interfaces, error: 50 - Local Database Runtime error occurred, before you begin you need to rename the v11 or v12 to (localdb)\mssqllocaldb

• You dont have the services running
• You don't have the firelwall ports here configured
• Your install has and issue/corrupt (the steps below help give you a nice clean start)
• You did not rename the V11 or 12 to mssqllocaldb

I found that the simplest is to do the below - I have attached the pics and steps for help.

First verify which instance you have installed, you can do this by checking the registry and by running cmd

1. cmd> Sqllocaldb.exe i
2. cmd> Sqllocaldb.exe s "whicheverVersionYouWantFromListBefore" if this step fails, you can delete with option d cmd> Sqllocaldb.exe d "someDb"
3. cmd> Sqllocaldb.exe c "createSomeNewDbIfyouWantDb"
4. cmd> Sqllocaldb.exe start "createSomeNewDbIfyouWantDb"