I'm new to publishing. I'm facing a problem.please help me

Network path not found Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.ComponentModel.Win32Exception: Network path not found

Resource Error:

Line 16: public ActionResult Index ()
Line 17: {
Line 18: ViewBag.PersonelCount = db.TBLTags.Count ();
Line 19: ViewBag.MapsCount = db.TBLMaps.Count ();
Line 20: ViewBag.ReaderCount = db.TBLReaders.Count ();
    ````

Source File: D: \ ComidatUI \ ComidatPtsInformationSystem \ Controllers \ HomeController.cs Line: 18

Stack Tracking:


[Win32Exception (0x80004005): Network path not found]

[SqlException (0x80131904): A network related or instance specific error occurred while establishing a connection to the server. The server was not found or the server is unreachable. Verify that the instance name is correct and that SQL Server allows remote connections. (provider: Named Pipes Provider, error: 40 - Could not open connection to SQL Server)]