PHP

419 unknown status

//It's an error of csrf token, there is multiples ways to fix it, too much to 
//write a grepper answer on.

//419 : error of csrf token

//Common way to fix it, try this
$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
    }
});

POST http://... 419 (unknown status)

You are using laravel as backend and React as frontend or otherwise

solution:
1. Just rewrite your top domain on to match themselves.

example: 
(laravel) http://localhost:8000 and (react) http://localhost:3000/
or 
(laravel) http://127.0.0.1:8000 and (react) http://127.0.0.1:3000/

2. "Accept: application/json" to headers [optional depending on your client service]