如果电子邮件存在则出错 - codeigniter php

I am having following problem when i run forgot page the email check if working fine, but if the email is exists the mail sent section get following error not email was sent.

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User.php (controller)

public function forgot() {

// create the data object
$data = new stdClass();

// load form helper and validation library
$this->load->helper('form');
$this->load->library('form_validation');

$this->form_validation->set_rules('email', 'Email', 'required|valid_email'); 

if($this->form_validation->run() == FALSE) {
    // Load this page with error
    $this->load->view('header');
    $this->load->view('user/forgot/forgot');
    $this->load->view('footer');
}else{
    $email = trim($this->input->post('email'));  
    //$clean = $this->security->xss_clean($email);
    $userInfo = $this->user_model->checkUserEmail($email);

    if($userInfo) {
        $this->password_to_email($email, $userInfo);
        $this->load->view('header');
        $this->load->view('user/forgot/password_sent', array('email' => $email));
        $this->load->view('footer');
    } else {
        $data->error = 'We cant find your email address.';

        $this->load->view('header');
        $this->load->view('user/forgot/forgot', $data);
        $this->load->view('footer');
    }

}

}

private function password_to_email($email, $firstname) { $this->load->library('email');

$from_email = "test@test.com";

$token = md5($this->config->item('salt') . $firstname);

$this->email->set_mailtype('html');
$this->email->from($from_email);
$this->email->to($email);
$this->email->message('Reset your Password');

$message = '<html><body>';
$message .= '<p>Hello '.$firstname.'</p>';
$message .= '<p>Please use following link to reset your password.<br><a href="'.base_url().'reset/reset/'.$email.'/'.$token.'"></a></p>';
$message .= '<p>Thank you!</p>';
$message .= '</body></html>';

$this->email->message($message);
$this->email->send();

}

Well you've not shown your model for $this->password_to_email($email, $userInfo); so I just have to guess a little here.

The Clue is in the Error

Message:Object of class stdClass could not be converted to string.

But what will be happening is that $firstname in

$token = md5($this->config->item('salt') . $firstname);

needs to be a string and you are passing in an object from your DB query.

So your call to

$this->password_to_email($email, $userInfo);

would need to be something like

$this->password_to_email($email, $userInfo->firstname);

So you need to ensure you are passing in a string.

Performing var_dump($userInfo);in say...

...
}else{
    $email = trim($this->input->post('email'));  
    //$clean = $this->security->xss_clean($email);
    $userInfo = $this->user_model->checkUserEmail($email)
    var_dump($userInfo);
...

Will show you the format of what $userInfo actually is. Then you can go from there. You just need to ensure you are getting $firstname as a string.