Encrypting App.Config Section and deploying to multiple machines

I've done a lot of reading around and am trying to encrypt a section in a WPF App.Config file. I am not using the default section, but rather a custom one . I have an app where the user specifices a .config file and the app reads this file in order to update keys.

In order to decrypt and encrypt my file section I am using the following code:

var configMap = new ExeConfigurationFileMap { ExeConfigFilename = this.FileName };
var config = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);
var configSection = config.GetSection(Section);

if (!configSection.SectionInformation.IsProtected)
   if (!configSection.ElementInformation.IsLocked)
     {
          configSection.SectionInformation.ProtectSection("RsaProtectedConfigurationProvider");
          configSection.SectionInformation.ForceSave = true;
          config.Save(ConfigurationSaveMode.Full);
     }

and to Decrypt:

var configMap = new ExeConfigurationFileMap { ExeConfigFilename = this.FileName };
var config = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);
var configSection = config.GetSection(Section);

if (configSection.SectionInformation.IsProtected)
{
    configSection.SectionInformation.UnprotectSection();
    configSection.SectionInformation.ForceSave = true;
    config.Save(ConfigurationSaveMode.Full);
}

The problem I am facing is that if I have a file that is encrypted on Machine A and I place the file on Machine B, I cannot decrypt the .config file because the encryption was done on Machine A.

I've tried to follow the steps in several articles that recommend using aspnet_regiis to create and export key containers (link) and (link) but maybe i'm doing something wrong. My guess is that because i'm not using aspnet_regiis in order to encrypt the file or to decrypt the file I get stuck. Is there a way to do this without using the aspnet_regiis tool and the command line?

A lot of the information around is more for web.config vs app.config. Again, this is for a C#/WPF application using MVVM.

I was also looking at custom encryption (custom data provider), but all the examples i've seen are for web.config (link).