Why do I get 'Message rejected: Email address is not verified' when trying to send an SES email?

I am trying to send an email from email1 to email2. But I am getting the following error:

Transaction failed. The server response was: Message rejected: Email address is not verified. The following identities failed the check in region CA-CENTRAL-1: [email protected], Sender Name [email protected], [email protected]

Here is my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mail;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using System.Net.Mail;

namespace ConsoleApp3
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Email("DO TEST");
        }

        public static void Email(string htmlString)
        {


            String FROM = "[email protected]";
            String FROMNAME = "Sender Name";

    
            String TO = "[email protected]";

  
            String SMTP_USERNAME = "kiffretM5C2PFESI5W";


            String SMTP_PASSWORD = "BLeMDSkjioourdvhvbhvhTMHAVfuG6mcAXibbTmQpe7WX";


            String HOST = "email-smtp.ca-central-1.amazonaws.com";

     
            int PORT = 587;

            
            String SUBJECT =
                "Amazon SES test (SMTP interface accessed using C#)";

            // The body of the email
            String BODY =
                "<h1>Amazon SES Test</h1>" +
                "<p>This email was sent through the " +
                "<a href='https://aws.amazon.com/ses'>Amazon SES</a> SMTP interface " +
                "using the .NET System.Net.Mail library.</p>";

  
            MailMessage message = new MailMessage();
            message.IsBodyHtml = true;
            message.From = new MailAddress(FROM, FROMNAME);
            message.To.Add(new MailAddress(TO));
            message.Subject = SUBJECT;
            message.Body = BODY;
     

            using (var client = new System.Net.Mail.SmtpClient(HOST, PORT))
            {
                
                client.Credentials =
                    new NetworkCredential(SMTP_USERNAME, SMTP_PASSWORD);

                
                client.EnableSsl = true;


                try
                {
                    Console.WriteLine("Attempting to send email...");
                    client.Send(message);
                    Console.WriteLine("Email sent!");
                }
                catch (Exception ex)
                {
                    Console.WriteLine("The email was not sent.");
                    Console.WriteLine("Error message: " + ex.Message);
                }
            }
            }
    }
}