Error status 500 Ajax on Laravel

Good I am trying to delete through ajax but I get the following error:

Failed to load resource: the server responded with a status of 500 (Internal Server Error)

I searched the error and apparently appears by the token so I have done what they recommended, I added in the view this:

<meta name="csrf-token" content="">

and ajax:

        $('#delete').on('click', function(){
        var x = $(this);
        var delete_url = x.attr('data-href')+'/'+x.attr('data-id');

        $.ajax({
            url: delete_url,
            type:'DELETE',
            headers:{"X-CSRF-TOKEN": $('meta[name="csrf-token"]').attr('content')},
            success:function(result){
                alert('success');
            },
            error:function(result){
                alert('error');
            }

        });
    });

controller:

    public function destroy($id)
{
    $appointment = Appointment::find($id);

    if(appointment == null){
        return Response()->json([
            'message'=>'error delete.'
        ]);
    }

    $appointment->delete();
    return Response()->json([
            'message'=>'sucess delete.'
        ]);

}

via Chebli Mohamed