In Update Panel how to show alert message after click on button Asp.net

Question:-In Update Panel how to show alert message after click on button 

Answer:-
In Aspx.cs page    
ScriptManager.RegisterStartupScript(this, this.GetType(), "filesDeleted", "alert('helo')", true);

     

Email Error The remote certificate is invalid according to the validation procedure.

Question:- Email Error The remote certificate is invalid according to the validation procedure.

Answer:-
using System.Net.Mail;
using System.Net;
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;

// add below  code  before  send () method  like 

 SmtpClient client = new SmtpClient(); 

 ServicePointManager.ServerCertificateValidationCallback = delegate(object s, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) { return true; };

  client.send(msg);