Edit:
A whole series of new insights gained after asking this question have taught me what the issue was, and it definitely did not have anything to do with the described server migration.
The two given answers show how to "fix" this for both CakePHP 2 and 3, though bear in mind this might pose a security risk. The CSRF component is an important security feature, and should not be disabled lightly.
Original question:
I migrated my CakePHP 3 project from XAMPP on my laptop to XAMPP on a server. Ever since when I activate the Security component, cake throws me an error. Here it is, directly from the Error log:
2016-05-21 20:32:01 Error: [Cake\Controller\Exception\AuthSecurityException] '_Token' was not found in request data.
Request URL: /Users/addUser
Referer URL: http://localhost/users/add_user
Stack Trace:
#0 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Controller\Component\SecurityComponent.php(324): Cake\Controller\Component\SecurityComponent->_validToken(Object(App\Controller\UsersController))
#1 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Controller\Component\SecurityComponent.php(130): Cake\Controller\Component\SecurityComponent->_validatePost(Object(App\Controller\UsersController))
#2 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Event\EventManager.php(386): Cake\Controller\Component\SecurityComponent->startup(Object(Cake\Event\Event))
#3 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Event\EventManager.php(356): Cake\Event\EventManager->_callListener(Array, Object(Cake\Event\Event))
#4 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Event\EventDispatcherTrait.php(78): Cake\Event\EventManager->dispatch(Object(Cake\Event\Event))
#5 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Controller\Controller.php(495): Cake\Controller\Controller->dispatchEvent('Controller.star...')
#6 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Routing\Dispatcher.php(109): Cake\Controller\Controller->startupProcess()
#7 C:\xampp\htdocs\vendor\cakephp\cakephp\src\Routing\Dispatcher.php(87): Cake\Routing\Dispatcher->_invoke(Object(App\Controller\UsersController))
#8 C:\xampp\htdocs\webroot\index.php(37): Cake\Routing\Dispatcher->dispatch(Object(Cake\Network\Request), Object(Cake\Network\Response))
#9 {main}
I found CakePHP security component blackholing login (data[_Token][key] field not generated), here on StackOverflow, but no other relevant information as to what's causing my problem. In my Appcontroller:
public function initialize()
{
parent::initialize();
$this->loadComponent('Security');
$this->loadComponent('RequestHandler');
$this->loadComponent('Flash');