The ConnectionString property has not been initialized.

I am trying to use a connection string from web.config file for the first time. Here is my code.

Try
Dim cmd As String = _
("SELECT [Name], BirthDate, StartDate From " & _
"Employees WHERE PayGroup='20' AND Status='A'")

Dim conn As String = _
System.Configuration. _
ConfigurationManager. _
AppSettings("myConString")

Dim myConn As New SqlConnection(conn)
Dim myCmd As New SqlDataAdapter(cmd, myConn)
Dim ds As New DataSet
myCmd.Fill(ds)
gvEmp.DataSource = ds
gvEmp.DataBind()

Catch ex As Exception
Response.Write(ex.Message & "<br>")
Finally

End Try

I am getting The ConnectionString property has not been initialized. What am I doing wrong?Show your web.config code.
<connectionStrings>
<add name="myConString" connectionString="Data Source=myServer;Initial Catalog=Employees;User ID=myUser;Password=mypass"
providerName="System.Data.SqlClient" />
</connectionStrings>