Asp.net MVC Connection - asp.net-mvc

Question

I have multiple Web applications running on the same server. All are MVC.
I created a new Asp.Net MVC app and placed it on the server. Changed the Connection String values and it's throws the following error. I am stumped with this. SQL Server is set to allow remote connections. Connection String references the correct named instance.
This is my connection string in web.config
<connectionStrings>
<add name="RAD_SystemEntities" connectionString="metadata=res://*/Models.RADSystem.csdl|res://*/Models.RADSystem.ssdl|res://*/Models.RADSystem.msl;provider=System.Data.SqlClient;provider connection string="Data Source=ServerName\NAMED_INSTANCE;Initial Catalog=RAD_System;Integrated Security=False;Persist Security Info=False;User ID=sa;Password=sa"" providerName="System.Data.EntityClient" />
</connectionStrings>
Following is 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: SQL
Network Interfaces, error: 26 - Error Locating Server/Instance
Specified) 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.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)
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace below.
Stack Trace:
[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)]
TotalDesk.Controllers.HomeController.Index(User model) +7147
lambda_method(Closure , ControllerBase , Object[] ) +104
System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase
controller, Object[] parameters) +14
System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext
controllerContext, IDictionary2 parameters) +181
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext
controllerContext, ActionDescriptor actionDescriptor, IDictionary2
parameters) +27
System.Web.Mvc.Async.<>c__DisplayClass42.b__41()
+28 System.Web.Mvc.Async.<>c__DisplayClass81.<BeginSynchronous>b__7(IAsyncResult
_) +10 System.Web.Mvc.Async.WrappedAsyncResult1.End() +50 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult
asyncResult) +32
System.Web.Mvc.Async.<>c__DisplayClass39.b__33()
+58 System.Web.Mvc.Async.<>c__DisplayClass4f.b__49()
+225 System.Web.Mvc.Async.<>c__DisplayClass37.b__36(IAsyncResult asyncResult) +10 System.Web.Mvc.Async.WrappedAsyncResult1.End()
+50 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult
asyncResult) +34
System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20()
+24 System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult
asyncResult) +99 System.Web.Mvc.Async.WrappedAsyncResult1.End()
+50 System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult
asyncResult) +27
System.Web.Mvc.<>c__DisplayClass1d.b__18(IAsyncResult
asyncResult) +14
System.Web.Mvc.Async.<>c__DisplayClass4.b__3(IAsyncResult
ar) +23 System.Web.Mvc.Async.WrappedAsyncResult1.End() +55
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +39
System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult
ar) +23 System.Web.Mvc.Async.WrappedAsyncResult1.End() +55
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +29
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult
asyncResult) +10
System.Web.Mvc.<>c__DisplayClass8.b__3(IAsyncResult
asyncResult) +25
System.Web.Mvc.Async.<>c__DisplayClass4.b__3(IAsyncResult
ar) +23 System.Web.Mvc.Async.WrappedAsyncResult`1.End() +55
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
+31 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult
result) +9
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
+9667432 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

My issue was that I had the inccorect Entity Framework in my project to what was in the GAC. have changed my Entity Framework version to be the same as version in GAC and the issue has been resolved.
If you are doing the same. Please make sure to update the references in config files to the correct version

Answer 2

your problem is with the database -
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
cmd> Sqllocaldb.exe i
cmd> Sqllocaldb.exe s "whicheverVersionYouWantFromListBefore"
if this step fails, you can delete with option d cmd> Sqllocaldb.exe d "someDb"
cmd> Sqllocaldb.exe c "createSomeNewDbIfyouWantDb"
cmd> Sqllocaldb.exe start "createSomeNewDbIfyouWantDb"