I have not programmed in PHP for ages, but looking at the docs it seems that "Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE array." Your code seems to immediately redirect and the cookies array might not contain the just set cookie.

More important: what are you trying to achieve? Why do you have the need to reload the page?

Thanks for your reply Alexei. we have products from UK and products from US we need to load products and other site content based on cookie value, cookie value will be detect based on IP Geo. so for that i need to check cookie is set or not before page load. as per my code i checked if there's no cookie create new one. after create cookie i need to reload that page so that it will detect. cookie and load product and content based on that.

Right now what happen when i use header('Location: '.$_SERVER['REQUEST_URI']); it stop page loading i guess / loop many times not sure. so it shows error message. After 2 sec it redirect to REQUEST_URI, it's happen when ever cookie created first time.

I am wondering if it works if you change the server-side "reload" to a client-side one: location.reload()

I don't know if this will solve your issue, but I think it's better to call exit() after header():

header('Location: '.$_SERVER['REQUEST_URI']);   // reload
exit();

You can make it as a reusable function if you wish:

function goto_page(string $page): void
{
    header('Location: ' . $page);
    exit();
}

and call it like: goto_page($_SERVER['REQUEST_URI']);.