Massmailer/Massmailer.Shared/Logic/Mailer.cs

using MailKit.Net.Smtp;
using Massmailer.Shared.Model;
using MimeKit;
using System;
using System.Threading.Tasks;

namespace Massmailer.Shared.Logic
{
    public class Mailer : IMailer
    {
        private readonly SmtpSettings smtpSettings;

        public Mailer(SmtpSettings smtpSettings)
        {
            this.smtpSettings = smtpSettings;
        }

        public async Task SendMailAsync(string email, string subject, string body)
        {
            try
            {
                var message = new MimeMessage();
                message.From.Add(new MailboxAddress(this.smtpSettings.SenderName, this.smtpSettings.SenderEmail));
                message.To.Add(new MailboxAddress(email, email));
                message.Subject = subject;
                message.Body = new TextPart("html") { Text = body };

                using (var client = new SmtpClient())
                {
                    client.ServerCertificateValidationCallback = (s, c, h, e) => true;

                    await client.ConnectAsync(this.smtpSettings.Server, this.smtpSettings.Port, this.smtpSettings.UseSsl);
                    await client.AuthenticateAsync(this.smtpSettings.Username, this.smtpSettings.Password);
                    await client.SendAsync(message);
                    await client.DisconnectAsync(true);
                }
            }
            catch (Exception ex)
            {
                throw new InvalidOperationException(ex.Message);
            }
        }
    }
}