Does not log in with existing contacts using PTA

Summary:

Hello,

I am configuring PTA to use it from an external page.

If it is a new contact, it creates it as new and I can login correctly with the PTA URL.

The problem I have is that if it is an existing contact, either created by the API or created manually from the agent desk, it does not allow to login with the PTA URL and redirects to the login page.

I am passing the contact parameters without password, this is my script:

Code Snippet (add any code snippets that support your topic, if applicable):

<?php

   $ptaDataArray = array(