PHPMailer\PHPMailer\POP3::login PHP Method

    public function login($username = '', $password = '')
    {
        if (!$this->connected) {
            $this->setError('Not connected to POP3 server');
        }
        if (empty($username)) {
            $username = $this->username;
        }
        if (empty($password)) {
            $password = $this->password;
        }
        // Send the Username
        $this->sendString("USER {$username}" . self::CRLF);
        $pop3_response = $this->getResponse();
        if ($this->checkResponse($pop3_response)) {
            // Send the Password
            $this->sendString("PASS {$password}" . self::CRLF);
            $pop3_response = $this->getResponse();
            if ($this->checkResponse($pop3_response)) {
                return true;
            }
        }
        return false;
    }