Error 500 in API Laravel in Heroku only via POST

I have an API made in Laravel, I did all the local tests, everything ok, I loaded the Heroku, I ran the server, and I have the following situation:

In the local environment, all requests in any method work, POST, GET, DELETE, but in Heroku, I can only retrieve the routes that are via GET, I saw several answers both in the OS and here SOpt, / p>

The error I have is 500 (Internal Server Error) , with a json answer:

{
    "message": "Server Error"
}

I tried to authorize the proxies, I already have the key configured, I checked the path heroku.com and herokuapp.com , and neither works, I also tried HTTP and HTTPS , also without success, heroku logs they only return me a 500 error as well, without any further information.

My question is:

  

Is there any restriction on heroku to use something via POST?

     

I need a key other than APP_KEY to perform a POST to a   Heroku-hosted API?

     

Or finally, what do I need to do to correctly configure Heroku to receive a Laravel API?

OBS:

This API does not use a database.