Email Class takes hours to send email

[eluser]Unknown[/eluser]
Hi,

So we are using the email class to send emails such as verification emails, welcome emails, etc.

The problem is, the verification email takes too long to get received by our users- some users have reported waiting 4 hours to get it while others it took them an hour. I really don't know what could be causing this, majority of our vars are default.

Heres the emailing code;

Code:

$email = $this->User->get_email_by_hash($hash);
                $this->load->library('email');
                    
                $config['mailtype'] = 'html';
                
                $this->email->initialize($config);
                $this->email->from('[email protected]', 'Website');
                $this->email->to($email);    
                $this->email->subject('Welcome to Website');
                $this->email->message('HTML EMAIL HERE');    
    
                $this->email->send();

Could this be a host issue? We are hosted with MediaTemple.

Also we have tested it ourselves locally and it takes seconds, but when on our server sometimes it takes an hour.