Unable to send email using PHP SMTP. Your server might not be configured to send mail using this method

Change smtp_port from 465 to 587.

Make sure $config['newline'] = "\r\n"; is in double quotes not single quotes.

$mail_config['smtp_host'] = 'smtp.gmail.com';
$mail_config['smtp_port'] = '587';
$mail_config['smtp_user'] = '[email protected]';
$mail_config['_smtp_auth'] = TRUE;
$mail_config['smtp_pass'] = 'password';
$mail_config['smtp_crypto'] = 'tls';
$mail_config['protocol'] = 'smtp';
$mail_config['mailtype'] = 'html';
$mail_config['send_multipart'] = FALSE;
$mail_config['charset'] = 'utf-8';
$mail_config['wordwrap'] = TRUE;
$this->email->initialize($mail_config);

$this->email->set_newline("\r\n");

I just added the last line

Just use "mail" for the 'protocol' array item, and that's all...

$config = array();
        $config['useragent']    = $system_name;
        $config['mailpath']     = "/usr/bin/sendmail"; // or "/usr/sbin/sendmail"
        $config['protocol']     = "mail"; //use 'mail' instead of 'sendmail or smtp'
        $config['smtp_host']    = "your domain name";
        $config['smtp_user']    =  $from;
        $config['smtp_pass']    = "*************";
        $config['smtp_port']    =  465;
        $config['smtp_crypto']  = 'ssl';
        $config['smtp_timeout'] = "";
        $config['mailtype']     = "html";
        $config['charset']      = "utf-8";
        $config['newline']      = "\r\n";
        $config['wordwrap']     = TRUE;
        $config['validate']     = FALSE;