Why don't emails get through even though PHPMailer doesn't throw an error?

Question

PHPMailer

<?php
  use PHPMailer\PHPMailer\PHPMailer;
  use PHPMailer\PHPMailer\Exception;

  require 'phpmailer/src/Exception.php';
  require 'phpmailer/src/PHPMailer.php';

  $mail = new PHPMailer(true);
  $mail->CharSet = 'UTF-8';
  $mail->setLanguage('ru', 'phpmailer/language');
  $mail->isHTML(true);

// От кого письмо
$mail->setFrom('[email protected]','Тема письма');
// Кому отправитель
$mail->addAddress('[email protected]','Тема письма');
// Тема письма
$mail->Subject = 'Привет, письмо с сайта';

$body = '<h1>Письмо!</h1>';

if(trim(!empty($_POST['name']))){
  $body.='<p><strong>Имя:</strong> '.$_POST['name'].'</p>';
}
if(trim(!empty($_POST['email']))){
  $body.='<p><strong>Email:</strong> '.$_POST['email'].'</p>';
}
if(trim(!empty($_POST['phone']))){
  $body.='<p><strong>Phone:</strong> '.$_POST['phone'].'</p>';
}


$mail->Body = $body;

if (!$mail->send()){
  $message = 'Ошибка';
} else {
  $message = 'Данные отправлены';
}

$response = ['message' => $message];

header('Content-type: application/json');
echo json_encode($response);

?>

does not give an error, but the letter does not reach?
Tried two mail also does not send