[Solved ]:A network-related or instance-specific error occurred while establishing a connection to SQL Server

How to resolve “a network-related or instance-specific error occurred while establishing a connection to SQL Server” error.

Description:

While I am working on window application I have received 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: shared memory provider, error:40 could not open a connection. to sql server)”

This error is occurred when Sql server services stop working.

Solution:

To solve this error follow the below given steps:

Step 1: Go to Control panel and select Administrative tools.

Step 2: Administrative tools will be open and select services option.

Step 3: services window will be open and search for SQL server. There will be 2 options: Sql server (MSSQLSERVER) AND Sql server (SQLEXPRESS). You will be seeing the status of sql server is empty. In my case sql server (Sql express) stop working.

Step 4: Right click on sql server services (which stop working) and select Start option. 

Service control will be populated and close when it is done.

Now you will be see sql server services are started.

This solution work for me.