diff --git a/extension/Classes/Core/Helper/SessionCookie.php b/extension/Classes/Core/Helper/SessionCookie.php
index 80e62a9b394865e27460a9b99ae1e1b7b9b37b1f..3f4f848df6c377ea462d3d98f785a7f590fce9e6 100644
--- a/extension/Classes/Core/Helper/SessionCookie.php
+++ b/extension/Classes/Core/Helper/SessionCookie.php
@@ -71,6 +71,7 @@ class SessionCookie {
 
 //            $this->arrCookieString[] = "name:$key,value:$value,url:$domain,path:$path";
             // qfqpdf seems to have problems if 'domain' is specified: it hangs by fetching the website. Skip domain.
+            // qfqpdf generates another cookie for pdf (SIPs then not reachable) if the given domain doesnt equal what is set in cookie params. Domain default from qfqpdf is without dot. We need to give the domain with previous dot.
             $this->arrQfqPdfCookie[] = "name:$key,value:$value,domain:.$domain";
         }
         $linesForWkhtml = '';
diff --git a/extension/Classes/Core/Store/Session.php b/extension/Classes/Core/Store/Session.php
index 7671274d511824b131cd1e2e56c5599b75e73436..8835d9927b4e207a87dcffdbb485f72f8fbbb32c 100644
--- a/extension/Classes/Core/Store/Session.php
+++ b/extension/Classes/Core/Store/Session.php
@@ -58,6 +58,7 @@ class Session
             // Needed expire date for header() method
             $expireDate = date("D, d-M-Y H:i:s", strtotime('+2 days')). ' GMT';
 
+            // More information about previous dots in domains: https://stackoverflow.com/questions/348282/php-cookie-domain-subdomain-control
             if(PHP_VERSION_ID < 70300) {
                 session_set_cookie_params($lifetime, $path.';SameSite='.$samesite, $_SERVER['HTTP_HOST'], $secure, $httponly);
             } else {