View file ProForum/Files/application/app/Http/Middleware/AuthenticateApi.php

<?php

namespace App\Http\Middleware;

use Illuminate\Auth\Middleware\Authenticate as Middleware;
class AuthenticateApi extends  Middleware
{
    /**
     * Get the path the user should be redirected to when they are not authenticated.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return string|null
     */


    protected function redirectTo($request)
    {
        if (!$request->expectsJson()) {
            return route('api.unauthenticate');
        }
    }

}