Cookie session is not installed only in IE11

Question

Cookie session is not installed only in IE11

A curious problem.

The newly developed website uses a third-party login system that uses sessions (surprise!). The website works fine in all instances, in all browsers except Internet Explorer 11 (and, possibly, previous versions, not checked).

Qualifiers:

I read various related topics on SO, nothing matches the bill.
PHP Header does not redirect to each affected page
no _ in the domain name or URL.
No frames.
Session and domain are protected.

Code Details:

a) Each page has a controller file with header information included in it:

 header("Cache-Control: no-cache, must-revalidate"); //HTTP 1.1 header("Expires: Thu, 19 Nov 2011 08:52:00 GMT"); // Date in the past header('Content-Type: text/html; charset=utf-8'); header("X-Clacks-Overhead: GNU Terry Pratchett"); header_remove("X-Powered-By"); header("X-XSS-Protection: 1; mode=block"); header("X-Frame-Options: SAMEORIGIN"); header("X-Content-Type-Options: nosniff"); header("Content-Language: en"); header("Content-Security-Policy: upgrade-insecure-requests;"); header("Referrer-Policy: origin-when-cross-origin"); //referrer for Chrome header("Referrer-Policy: strict-origin-when-cross-origin"); if (isset($_SERVER['HTTP_USER_AGENT']) && (strpos($_SERVER['HTTP_USER_AGENT'], 'MSIE') !== false)){ header('X-UA-Compatible: IE=edge,chrome=1'); }

b) as part of this process; A cookie check is performed to see if cookies are enabled in the client browser. This is done through both the login / access and sharing zones.

 if($_COOKIE['cookieEnabled'] !== "yes") { \setcookie('cookieEnabled', "yes", time() + 42000, "/", $_SERVER['HTTP_HOST'], true, true); }

All that is is a cookie that says yes, cookies are included if the cookie is not already set. Just.

c) Below that; There is a controller code for loading session variables and performing other actions for a third-party administrator.

 // Create / Include the Session Object - Session.php $session = new Session($db);

d) I set the test status in Session.php __construct to do this:

  session_start(); if($_COOKIE['cookieEnabled'] !== "yes" && empty($_SESSION)) { error_log("INFO: An access attempt without a session or cookie was attempted..."); if($_COOKIE['cookieEnabled'] !== "yes"){ error_log("Cookie does not appear to be enabled"); } die("unimportant debug error"); }

Note that the session array will never be empty, as it has been previously added to previous pages;

e) [local] PHP.ini:

 session.cookie_secure=1 default.charset=utf-8 error_log=/home/domainaccount/error/PHP_error.log session.save_path=/home/domainaccount/sessionz session.cookie_domain=domain.org.uk

NOTE. Web path: /home/domainaccount/public_html/

PHP.ini values were checked with phpinfo() and set correctly.

Curious problem

I load the website into various browsers, and it registers in order, all work, session data is transferred.

However, this is not the case on IE11. It simply returns with a blank screen, without errors, without feedback (otherwise, session data is transferred to the login page) and there are no code error logs .

The error log shows:

INFO: an attempt was made to access without a session or cookie ...

A whole bunch of times, but no indication that the cookie was refused, just a session.

Unsurprisingly, the login page has a Header location redirect for success and failed login attempts.

About IE11

IE version number: 11.248.16299.0.
IE cookie settings: first cookies are accepted, third-party cookies are accepted, session cookies are always allowed.