Añadir controlador de SMS

public IConfiguration Configuration { get; set; }

public SmsController(IConfiguration config)
{
    Configuration = config;
}

[HttpPost]
public IActionResult Sms(Models.SmsModel sendSmsModel)
{
    if (ModelState.IsValid)
    {
        try
        {
            var VONAGE_API_KEY = Configuration["VONAGE_API_KEY"];
            var VONAGE_API_SECRET = Configuration["VONAGE_API_SECRET"];
            var credentials = Credentials.FromApiKeyAndSecret(VONAGE_API_KEY, VONAGE_API_SECRET);
            var client = new SmsClient(credentials);
            var request = new SendSmsRequest { To = sendSmsModel.To, From = sendSmsModel.From, Text = sendSmsModel.Text };
            var response = client.SendAnSms(request);
            ViewBag.MessageId = response.Messages[0].MessageId;
        }
        catch(VonageSmsResponseException ex)
        {
            ViewBag.Error = ex.Message;
        }
    }
    return View("Index");
}