Cannot be able to encrypt the connectionstring in web.config file!

Hi,
I am trying to encrypt the connection string that is stored in web.config file by programming. However, i am not being able to do that. Below is my code:-

using System.Web.Configuration;
using System.Web.Security;
using System.Configuration;
 
public void EncryptConnString()
    {
     
Configuration config = WebConfigurationManager.OpenWebConfiguration(Request.ApplicationPath);
       ConfigurationSection section = config.GetSection("connectionStrings");
        if (!section.SectionInformation.IsProtected)
        {
            section.SectionInformation.ProtectSection("RsaProtectedConfigurationProvider");
            config.Save();
        }
    }

Please suggest me some measures and if i am wrong correct me...

Thanks and Regards
Akiii