I get error when I use myConnection insted of DefaultConnection

I can't understand this if I use name = DefaultConnection as in this example here it works

 <connectionStrings>
      <add name="DefaultConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\WebFormsIdentity.mdf;Initial Catalog=WebFormsIdentity;Integrated Security=True"
            providerName="System.Data.SqlClient" />
  </connectionStrings>

but if I instead change name from DefaultConnection to MyConnection as in this example

 <connectionStrings>
      <add name="MyConnection" connectionString="Data Source=(LocalDb)\v11.0;AttachDbFilename=|DataDirectory|\WebFormsIdentity.mdf;Initial Catalog=WebFormsIdentity;Integrated Security=True"
            providerName="System.Data.SqlClient" />
  </connectionStrings>

I get this error

{"Invalid column name 'Email'.\r\nInvalid column name 'EmailConfirmed'.\r\nInvalid column name 'PhoneNumber'.\r\nInvalid column name 'PhoneNumberConfirmed'.\r\nInvalid column name 'TwoFactorEnabled'.\r\nInvalid column name 'LockoutEndDateUtc'.\r\nInvalid column name 'LockoutEnabled'.\r\nInvalid column name 'AccessFailedCount'.\r\nInvalid column name 'Email'.\r\nInvalid column name 'EmailConfirmed'.\r\nInvalid column name 'PhoneNumber'.\r\nInvalid column name 'PhoneNumberConfirmed'.\r\nInvalid column name 'TwoFactorEnabled'.\r\nInvalid column name 'LockoutEndDateUtc'.\r\nInvalid column name 'LockoutEnabled'.\r\nInvalid column name 'AccessFailedCount'.\r\nInvalid column name 'UserId'.\r\nInvalid column name 'UserId'.\r\nInvalid column name 'Email'.\r\nInvalid column name 'EmailConfirmed'.\r\nInvalid column name 'PhoneNumber'.\r\nInvalid column name 'PhoneNumberConfirmed'.\r\nInvalid column name 'TwoFactorEnabled'.\r\nInvalid column name 'LockoutEndDateUtc'.\r\nInvalid column name 'LockoutEnabled'.\r\nInvalid column name 'AccessFailedCount'."}

The code is below and the error occurs when this row executes  IdentityResult result = manager.Create(user, Password.Text);

//I just create a new user my enter username password and confirm password
protected void CreateUser_Click(object sender, EventArgs e)
        {
            var userStore = new UserStore<IdentityUser>();
            var manager = new UserManager<IdentityUser>(userStore);

            var user = new IdentityUser() { UserName = UserName.Text };
            IdentityResult result = manager.Create(user, Password.Text);

            if(result.Succeeded)
            {
                StatusMessage.Text = string.Format("User {0} was created successfully!", user.UserName);
            }
            else
            {
                StatusMessage.Text = result.Errors.FirstOrDefault();
            }
        }

So why is it not possible to use another name then DefaultConnection

//tony