Why is it always an error 404?

Question

<?php

$shouji ='Sell yourself and buy an apple';

$str = "$shouji Why not?";

echo $ str

?>

Answer 1

It's done, thank you bro

Answer 2

It’s a problem with the programmer configuration, please change the port to 80

In addition, it is not recommended to use the browser’s automatic debugging function, manual debugging is the behavior of an expert