Почему не отправляется письмо?

Всех приветствую! Нужно сделать так, чтобы скрипт отправлял письмо на email. Письмо доходит до адресата, но оно почему-то пустое. Что я делаю не так?

Вот заголовки письма:

Date: Mon, 11 Jun 2018 4:53:21 +0300 (MSK/MSD)
From: <from@domen.ru>
X-Mailer: Yamail [ http://yandex.ru ] 5.0
Reply-To: <from@domen.ru>>
X-Priority: 3 (Normal)
Message-ID: <1528692801@salettalocal.ru>
Subject: Тема письма
MIME-Version: 1.0
Content-type: multipart/mixed; boundary="-----SD6ty54H54JDGSHJD"
To: <gfdgfd@mai.ru>

-----SD6ty54H54JDGSHJD
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 8bit


<p>Hello world!</p>
-----SD6ty54H54JDGSHJD--
.

<?php
class Mail {
	private $smtpConnect;
	private $login, $password;
	private $path;
	private $separator = '-----SD6ty54H54JDGSHJD';
	
	public function __construct($login, $password) {
		$this->login = $login;
		$this->password = $password;
		
		$this->smtpConnect = fsockopen('mail.saletta.ru', 25, $errno, $errstr, 10);
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, "EHLO mail.saletta.ru\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, "AUTH LOGIN\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, base64_encode($login) . "\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, base64_encode($password) . "\r\n");
		$data = $this->getData($this->smtpConnect);
	}
	
	public function send($to, $msg, $files = []) {
		$this->path = 'templates/texts/emails/' . $msg . '.tpl';
		if(!file_exists($this->path)) {
			$this->close();
			exit('Файл почты <b>' . basename($this->path) . '</b> не существует');
		}
		
		$msg = file_get_contents($this->path);
		$subject = $this->getSubject($msg);
		$text = $this->getHeadersByText($this->getText($msg));
		$headers = $this->getHeaders($to, $subject);
		
		if(!empty($files)) $text = $this->addFiles($text, $files);
		
		if(is_array($to)) {
			$result = [];
			for($i = 0, $count = count($to); $i < $count; $i++) {
				$headers .= 'To: <' . $to[$i] . ">\r\n";
				$result[] = $this->sendMail($this->login, $to[$i], $headers, $text);
			} return $result;
		}
		$headers .= 'To: <' . $to . ">\r\n";
		return $this->sendMail($this->login, $to, $headers, $text);
	}
	
	private function sendMail($from, $to, $headers, $text) {
		fputs($this->smtpConnect, 'MAIL FROM:' . $from . "\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, 'RCPT TO:' . $to . "\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, "DATA\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, $headers . "\r\n" . $text . "\r\n" . $this->separator . "--\r\n.\r\n");
		$data = $this->getData($this->smtpConnect);
		
		fputs($this->smtpConnect, "RSET\r\n");
		$data = $this->getData($this->smtpConnect);
		return $data;
	}
	
	public function close() {
		fputs($this->smtpConnect, "QUIT\r\n");
		$data = $this->getData($this->smtpConnect);
		return $data;
	}
	
	private function getData($smtpConnect) {
		$data = '';
		while($str = fgets($smtpConnect, 515)) {
			$data .= $str;
			if(substr($str, 3, 1) == ' ') break;
		} return $data;
	}
	
	private function getHeaders($to, $subject) {
		$headers = 'Date: ' . date('D, j M Y G:i:s') . " +0300 (MSK/MSD)\r\n";
		$headers .= 'From: <' . $this->login . ">\r\n";
		$headers .= "X-Mailer: Yamail [ http://yandex.ru ] 5.0\r\n";
		$headers .= 'Reply-To: <' . $this->login . ">\r\n";
		$headers .= "X-Priority: 3 (Normal)\r\n";
		$headers .= 'Message-ID: <' . time() . '@' . Config::ADDRESS2 . ">\r\n";
		$headers .= 'Subject: ' . $subject . "\r\n";
		$headers .= "MIME-Version: 1.0\r\n";
		$headers .= "Content-type: multipart/mixed; boundary=\"" . $this->separator . "\"\r\n";
		return $headers;
	}
	
	private function getHeadersByText($text) {
		$headers = $this->separator . "\r\n";
		$headers .= "Content-Type: text/html; charset=utf-8\r\n";
		$headers .= "Content-Transfer-Encoding: 8bit\r\n";
		$text = $headers . $text;
		return $text;
	}
	
	private function getSubject($msg) {
		$pattern = '/\{subject\}(.*)\{\/subject\}/';
		preg_match($pattern, $msg, $m);
		return $m[1];
	}
	
	private function getText($msg) {
		$pattern = '/\{subject\}(.*)\{\/subject\}/';
		$msg = preg_replace($pattern, '', $msg, 1);
		return $msg;
	}
	
	private function addFiles($text, $files) {
		for($i = 0, $count = count($files); $i < $count; $i++) {
			$name = basename($files[0]);
			
			$text .= "\r\n\r\n" . $this->separator . "\r\n";
			$text .= "Content-Type: application/octet-stream; name=\"$name\"\r\n";
			$text .= "Content-transfer-encoding: base64\r\n";
			$text .= "Content-Disposition: attachment; filename=\"$name\"\r\n";
			$text .= chunk_split(base64_encode(fread(fopen($files[0], 'rb'), filesize($files[0]))));
		}
		return $text;
	}
}