502 Bad Gateway nginx/1.11.3

Hello, I don't know if this is the right place for my question, but still, Forge is part of what I'm using.

I'm using Digital Ocean and Forge for a Laravel 5.3 project. My client has a CodeIgniter project that wants me to transfer to that server, so I created a subdomain site and deployed the repository.

The landing workds just great, but as soon as I want to go login by AJAX, it just doesn't work. It throws the error in the title in the response:

502 Bad Gateway  nginx/1.11.3

Is it something related with Forge? Because I tried it on my Homestead and it works just fine. How can I fix it?

Thanks in advance for your support!