Failed to connect to server: SMTP connect() failed. PhpMailer()

SMTP ERROR: Failed to connect to server: (0) 2020-07-26 10:39:34 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

 $mail = new PHPMailer;
             $mail->IsSMTP();
             $mail->SMTPDebug = 2;
           
             $mail->Host = 'mail.yourdomain.com';
                 
                 
             $mail->Port= '465';     //587  465
             $mail->SMTPAuth = TRUE;
             $mail->Username= 'user@yourdomain.com';
             $mail->Password ='password';

             $mail->SMTPSecure= 'ssl';
             //$mail->SMTPAuth = SMTP_AUTH;
           
             $mail->setFrom = 'user@domain.com';
             $mail->FromName= 'User name';

             $mail->AddAddress(hello@yourdomain.com, Testing);
             $mail->WordWrap =50;
             $mail->IsHTML= TRUE;
             $mail->Subject = 'Forget Password';

             $mail->MsgHTML('Testing');
              $mail->IsHTML(true);


below these lines paste this
---------------------------------------------------------------------------
 $mail->SMTPOptions = array(
'ssl' => array(
'verify_peer' => false,
'verify_peer_name' => false,
'allow_self_signed' => true
)
);
---------------------------------------------------------------------------

Why it shows error?
It worked successfully. The problem however is it's a bad idea because it goes against the whole idea of sending mail securely from one application to another.