$url = 'https://вашсайт/smtp_error.php';
$data = array('domain' => $_SERVER["SERVER_NAME"], 'smtp_error' => 'error');
$options = array(
'http' => array(
'header' => "Content-type: application/x-www-form-urlencoded\r\n",
'method' => 'POST',
'content' => http_build_query($data)
)
);
$context = stream_context_create($options);
$result = file_get_contents($url, false, $context);