Error: An Internal Error Has Occurred.

Stack Trace
APP/Vendor/cakephp/cakephp/lib/Cake/Network/Email/MailTransport.php line 51 → MailTransport->_mail(string, string, string, string, null)
        $message = implode($eol, $email->message());

        $params = isset($this->_config['additionalParameters']) ? $this->_config['additionalParameters'] : null;
        $this->_mail($to, $subject, $message, $headers, $params);
        return array('headers' => $headers, 'message' => $message);
APP/Vendor/cakephp/cakephp/lib/Cake/Network/Email/CakeEmail.php line 1121 → MailTransport->send(CakeEmail)

        $this->_message = $this->_render($this->_wrap($content));

        $contents = $this->transportClass()->send($this);
        if (!empty($this->_config['log'])) {
APP/Model/EventRegistration.php line 242 → CakeEmail->send()
APP/Model/EventRegistration.php line 256 → EventRegistration->sendEmailNotification(array)
array(
    'EventRegistration' => array(
        'id' => '54536294-9bf0-4cf7-ac98-7a960ab5c523',
        'agenda_item_id' => '5671',
        'company_type_id' => '11',
        'title_id' => '1',
        'country_id' => '8',
        'user_id' => '13',
        'user_type_id' => '39',
        'company_name' => 'PSA Publishers LTD',
        'company_website' => 'http://www.world-architects.com',
        'first_name' => 'Falk',
        'last_name' => 'Romano',
        'zip' => '8005',
        'po_box' => '',
        'city' => 'Zürich',
        'street' => 'Ausstellungsstrasse 25',
        'street2' => '',
        'phone' => null,
        'mobile' => '',
        'fax' => '',
        'tos' => true,
        'created' => '2014-10-31 11:21:08',
        'modified' => '2014-10-31 11:21:08',
        'state_id' => '53',
        'email' => 'fr@world-architects.com',
        'ticket_send' => false
    ),
    'AgendaItem' => array(
        'id' => '5671',
        'title' => 'Domotex 2015 / Tour 1 : André Schmidt',
        'image' => null,
        'description' => 'André Schmidt was trained at the Ecole Nationale Supérieure d’Architecture de Paris-Belleville and at the Technical University of Karlsruhe, KIT. Shortly after his graduation he first joined OMA Asia in 2000 in Hong Kong, where he worked on projects in Korea such as the SK-Telecom Headquarters building in Seoul. Back in Europe he gained further experience with the German-French firm Labfac on various projects in Germany before he joined OMA / Rem Koolhaas in Rotterdam for the CCTV headquarters project in 2003. André started with the masterplanning and later joining the team for CCTV’s sibling TVCC. In 2005 he transferred to Beijing, where he acted as project architect for TVCC. During this pre-olympic period, he has published a book on Beijings rapid urban transformation. André successfully led the design competition for the Taipei Performing Arts Center, which is currently under construction. He stayed with OMA as Associate until January 2009, when he relocated to New York to take on a teaching assignment as visiting critic at Rhode Island School of Design (RISD) in Providence. In 2010 André moved to Denmark to work with Bjarke Ingels Group, BIG. As project director and Associate he lead numerous large scale projects, including super-tall high rise projects, gaining further extensive international work experience within Europe and Asia. André stayed with BIG until end of 2013. Since 2014 André is the principal of MATTER, a practice for Architecture and Urbanism based in Berlin.',
        'organizer' => '',
        'start_date' => '2015-01-17 15:30:00',
        'end_date' => '2015-01-17 17:30:00',
        'email' => 'pp@world-architects.com',
        'url1' => '',
        'link_text1' => '',
        'url2' => '',
        'link_text2' => '',
        'link_text' => '',
        'active' => '1',
        'created' => '2014-10-30 08:44:07',
        'modified' => '2014-10-30 09:21:09',
        'parent_id' => '5600',
        'location_id' => '3589',
        'allow_registrations' => true,
        'Location' => array(
            [maximum depth reached]
        )
    ),
    'CompanyType' => array(
        'id' => '11',
        'parent_id' => '10',
        'name' => 'Architecture',
        'show_at_frontend' => true,
        'active' => true,
        'translation' => false,
        'lft' => '188',
        'rght' => '189',
        'sort_order' => '7',
        'created' => '2008-11-06 09:46:46',
        'modified' => '2012-02-08 10:49:35'
    ),
    'Title' => array(
        'id' => '1',
        'name' => 'Mr.',
        'active' => true,
        'translation' => false,
        'sort_order' => '1',
        'created' => '2010-06-03 10:26:16',
        'modified' => '2012-03-12 10:51:13'
    ),
    'User' => array(
        'password' => '*****',
        'id' => '13',
        'email' => 'fr@world-architects.com',
        'name' => '',
        'active' => true,
        'activation_code' => '',
        'last_login' => '2014-10-31 08:20:33',
        'can_manage_company_jobs' => true,
        'first_mail_sent' => false,
        'old_password' => '',
        'unencrypted_password' => '',
        'registered_from' => '',
        'registered_using' => '',
        'company_type_id' => '11',
        'created' => '2008-10-14 09:40:08',
        'modified' => '2014-10-31 08:20:33',
        'company_id' => '7',
        'role' => 'site_admin',
        'email_verified' => true,
        'email_token' => null,
        'email_token_expires' => null,
        'tos' => false,
        'tmp_image_id' => '533552b0-ed78-4ace-a21d-216dd5ae2926',
        'password_token' => null,
        'UserInfo' => array(
            [maximum depth reached]
        ),
        'username' => 'Falk Romano'
    ),
    'Country' => array(
        'id' => '8',
        'currency_id' => '6',
        'country' => 'Switzerland',
        'continent' => 'Europe',
        'iso_2' => 'CH',
        'iso_3' => 'CHE',
        'ioc' => 'CHF',
        'phone_prefix' => '+41',
        'need_to_buy_credits' => true,
        'vat_percent' => '8',
        'sort_order' => '6',
        'jobs_active_automatically' => false,
        'active' => true,
        'translation' => false,
        'created' => '2008-10-14 09:32:58',
        'modified' => '2012-04-27 10:05:40'
    )
)
[internal function] → EventRegistration->afterSave(boolean, array)
APP/Vendor/cakephp/cakephp/lib/Cake/Event/CakeEventManager.php line 245 → call_user_func_array(array, array)
APP/Vendor/cakephp/cakephp/lib/Cake/Model/Model.php line 1861 → CakeEventManager->dispatch(CakeEvent)
APP/Controller/EventRegistrationsController.php line 62 → Model->save(array)
[internal function] → EventRegistrationsController->add(string)
APP/Vendor/cakephp/cakephp/lib/Cake/Controller/Controller.php line 490 → ReflectionMethod->invokeArgs(EventRegistrationsController, array)
APP/Controller/AppController.php line 612 → Controller->invokeAction(CakeRequest)
APP/Vendor/cakephp/cakephp/lib/Cake/Routing/Dispatcher.php line 185 → AppController->invokeAction(CakeRequest)
APP/Vendor/cakephp/cakephp/lib/Cake/Routing/Dispatcher.php line 160 → Dispatcher->_invoke(EventRegistrationsController, CakeRequest, CakeResponse)
APP/webroot/index.php line 99 → Dispatcher->dispatch(CakeRequest, CakeResponse)