SMTP Error Could not authenticate in PHPMailer

Question

I want to send emails in Gmail using PHP Mailer in a Simple Script but I am getting an error:

SMTP Error: Could not authenticate. Error: SMTP Error: Could not authenticate.

SMTP server error: 5.7.1 Username and Password not accepted. Learn more at 535 5.7.1 http://mail.google.com/support/bin/answer.py?answer=14257 p38sm2467302ybk.16

I configured the OpenSSL For SSL/TLS Connections. 

This is my PHP Script:

 <?php

  require_once ("PHPMailer\class.phpmailer.php");

  $Correo = new PHPMailer();

  $Correo->IsSMTP();

  $Correo->SMTPAuth = true;

  $Correo->SMTPSecure = "tls";

  $Correo->Host = "smtp.gmail.com";

  $Correo->Port = 587;

  $Correo->UserName = "foo@gmail.com";

  $Correo->Password = "gmailpassword";

  $Correo->SetFrom('foo@gmail.com','De Yo');

  $Correo->FromName = "From";

  $Correo->AddAddress("bar@hotmail.com");

  $Correo->Subject = "Prueba con PHPMailer";

  $Correo->Body = "<H3>Bienvenido! Esto Funciona!</H3>";

  $Correo->IsHTML (true);

  if (!$Correo->Send())

  {

    echo "Error: $Correo->ErrorInfo";

  }

  else

  {

    echo "Message Sent!";

  }

?>

Can someone help me solve this issue?