How to Create A New SQL User For Aspnetdb Membership Db?

I have created a membership database using the `asp_regsql.exe` tool instead of the default wizard on an existing database.
When I create new user account with membership `createuser` method for `aspnetdb` membership database, I get below 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)_**

I am using VS 2013.  
my `aspnetdb` database name is : `SecurityTutorials.mdf`

Where is mycode error ?

my web.config setting :

<configuration><configSections><section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" /></configSections><connectionStrings><add name="newsdbConnectionString"
                 connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\newsdb.mdf;Integrated Security=True"
                 providerName="System.Data.SqlClient" /><add name="SecurityTutorialsConnectionString"
                 connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\SecurityTutorials.mdf;Integrated Security=True"
                 providerName="System.Data.SqlClient" /></connectionStrings><system.web><compilation debug="true" targetFramework="4.5"><assemblies><add assembly="System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" /></assemblies></compilation><httpRuntime targetFramework="4.5" /></system.web><appSettings><add key="ValidationSettings:UnobtrusiveValidationMode" value="None" /></appSettings><entityFramework><defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework"><parameters><parameter value="v11.0" /></parameters></defaultConnectionFactory><providers><provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" /></providers></entityFramework></configuration>

my CreatingUserAccounts.aspx.cs code is :

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    using System.Web.Security;
    using System.Web.UI.HtmlControls;


    public partial class Membership_CreatingUserAccounts : System.Web.UI.Page
    {

    const string passwordQuestion = "What is your favorite color";
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack) SecurityQuestion.Text = passwordQuestion;

    }
    protected void CreateAccountButton_Click(object sender, EventArgs e)
    {
        MembershipCreateStatus createStatus;
        MembershipUser newUser = System.Web.Security.Membership.CreateUser(Username.Text,
            Password.Text,
            Email.Text,
            SecurityQuestion.Text,
            SecurityAnswer.Text,
            true, out createStatus);
        switch (createStatus)
        {
            case MembershipCreateStatus.Success:
                CreateAccountResults.Text = "The user account was successfully created!";
                break;

            case MembershipCreateStatus.DuplicateUserName:
                CreateAccountResults.Text = "There already exists a user with this username.";
                break;

            case MembershipCreateStatus.DuplicateEmail:
                CreateAccountResults.Text = "There already exists a user with this email address.";
                break;

            case MembershipCreateStatus.InvalidEmail:
                CreateAccountResults.Text = "There email address you provided in invalid.";
                break;

            case MembershipCreateStatus.InvalidAnswer:
                CreateAccountResults.Text = "There security answer was invalid.";
                break;

            case MembershipCreateStatus.InvalidPassword:
                CreateAccountResults.Text = "The password you provided is invalid. It must be seven characters long and have at least one non-alphanumeric character.";
                break;

            default:
                CreateAccountResults.Text = "There was an unknown error; the user account was NOT created.";
                break;
            }
        }
    }