I am trying to send message from server email to my gmail
WebMail.SmtpServer = "mail.marekjedrysiak.com";
WebMail.SmtpPort = 25;
WebMail.EnableSsl = true;
WebMail.UserName = "firstname.lastname@example.org";
WebMail.Password = "******";
WebMail.From = "email@example.com";
WebMail.Send("firstname.lastname@example.org", "Message from server",null);
This isn't an ASP.NET or C# related problem, your domain doesn't have an MX record. You can confirm this by checking http://www.mxtoolbox.com.
I see that your domain is registered with Tucows (Hover). In order to change your MX records:
If you need more help setting up or debugging your mail service, you should contact Hover's support. They can also advise you on what exactly to enter as the address of your mail server.