Errors "This action is unauthorized." using Form Request validations in Laravel 5.5+, 6.X & 7.X

I run with a similar problem some time ago when starting to use Form Request classes for data validation (using php artisan make:request UpdateUserRequest for example).

If you are using a Form Request to validate the data, then first of all, check that you set properly the authorization rule that will allow it to pass. This is handled by the authorize() method that must return a boolean, that by default is set to false:

namespace App\Http\Requests\Users;

use Illuminate\Foundation\Http\FormRequest;
use Illuminate\Support\Facades\Auth;

class UpdateUserRequest extends FormRequest
{
    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()   
    {
        /** 
         * By default it returns false, change it to 
         * something like this if u are checking authentication
         */
        return Auth::check(); // <------------------

        /** 
         * You could also use something more granular, like
         * a policy rule or an admin validation like this:
         * return auth()->user()->isAdmin();
         * 
         * Or just return true if you handle the authorization
         * anywhere else:
         * return true;
         */ 
    }

    public function rules()
    {
        // your validations...
    }

}

Make sure you return true on "authorize" method

public function authorize()
{
    return true;
}