это то, что у меня сработало
$email_config = Array(
'protocol' => 'smtp',
'smtp_host' => 'ssl://smtp.googlemail.com',
'smtp_port' => '465',
'smtp_user' => 'someuser@gmail.com',
'smtp_pass' => 'password',
'mailtype' => 'html',
'starttls' => true,
'newline' => "\r\n"
);
$this->load->library('email', $email_config);
$this->email->from('someuser@gmail.com', 'invoice');
$this->email->to('test@test.com');
$this->email->subject('Invoice');
$this->email->message('Test');
$this->email->send();