Doctrine and CodeIgniter 3 Does not recognize the class

Good morning everyone.

I'm creating a project with Doctrine, the problem is when I try to do something like this:

$message = $this->em->find('Entities\PdContact', 1);

From the model, I get the following error:

  

Class 'Entities \ PdContact' does not exist

I hope someone can help me, Thanks.