PHPMailer\PHPMailer\SMTP::sendCommand PHP Метод

    protected function sendCommand($command, $commandstring, $expect)
    {
        if (!$this->connected()) {
            $this->setError("Called {$command} without being connected");
            return false;
        }
        //Reject line breaks in all commands
        if (strpos($commandstring, "\n") !== false or strpos($commandstring, "\r") !== false) {
            $this->setError("Command '{$command}' contained line breaks");
            return false;
        }
        $this->client_send($commandstring . self::CRLF);
        $this->last_reply = $this->get_lines();
        // Fetch SMTP code and possible error code explanation
        $matches = [];
        if (preg_match("/^([0-9]{3})[ -](?:([0-9]\\.[0-9]\\.[0-9]) )?/", $this->last_reply, $matches)) {
            $code = $matches[1];
            $code_ex = count($matches) > 2 ? $matches[2] : null;
            // Cut off error code from each response line
            $detail = preg_replace("/{$code}[ -]" . ($code_ex ? str_replace('.', '\\.', $code_ex) . ' ' : '') . "/m", '', $this->last_reply);
        } else {
            // Fall back to simple parsing if regex fails
            $code = substr($this->last_reply, 0, 3);
            $code_ex = null;
            $detail = substr($this->last_reply, 4);
        }
        $this->edebug('SERVER -> CLIENT: ' . $this->last_reply, self::DEBUG_SERVER);
        if (!in_array($code, (array) $expect)) {
            $this->setError("{$command} command failed", $detail, $code, $code_ex);
            $this->edebug('SMTP ERROR: ' . $this->error['error'] . ': ' . $this->last_reply, self::DEBUG_CLIENT);
            return false;
        }
        $this->setError('');
        return true;
    }