diff --git a/background.js b/background.js
index 822f6295..441dfa76 100644
--- a/background.js
+++ b/background.js
@@ -802,7 +802,7 @@ if (typeof browser !== 'object') {
     }
   }
 
-  var set_var_sites =  ['cz.de', 'nzherald.co.nz', 'theglobeandmail.com'].concat(de_madsack_domains, de_madsack_custom_domains);
+  var set_var_sites =  ['cz.de', 'nzherald.co.nz', 'theglobeandmail.com'].concat(de_madsack_domains);
   function runOnTab_once_var(tab) {
     let tabId = tab.id;
     let url = tab.url;
@@ -1331,6 +1331,9 @@ ext_api.runtime.onMessage.addListener(function (message, sender) {
           rules = Object.values(defaultSites).filter(x => x.domain === group)[0];
           if (group === '###_usa_gannett')
             rules.amp_unhide = 1;
+          else if (group === '###_de_madsack')
+            if (!set_var_sites.includes(custom_domain))
+              set_var_sites.push(custom_domain);
         }
         if (rules) {
           customAddRules(custom_domain, rules);
diff --git a/changelog.txt b/changelog.txt
index 83fa01a0..880c7e96 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -7,6 +7,7 @@ Add LosAndes.com.ar (Grupo Clarin)
 Remove Hln.be (fix obsolete)
 Remove Lequipe.fr (fix obsolete)
 Fix Harper's Magazine (modal)
+Fix Madsack Mediengruppe (custom flex sites)
 Fix NK News (pro)
 Fix Quartz (newsletter)
 
diff --git a/contentScript.js b/contentScript.js
index b47fd08d..aa234051 100644
--- a/contentScript.js
+++ b/contentScript.js
@@ -10,7 +10,6 @@ var ca_gcm_domains = ['lesoleil.com'].concat(['latribune.ca', 'lavoixdelest.ca',
 var ca_torstar_domains = ['niagarafallsreview.ca', 'stcatharinesstandard.ca', 'thepeterboroughexaminer.com', 'therecord.com', 'thespec.com', 'thestar.com', 'wellandtribune.ca'];
 var de_funke_medien_domains = ['abendblatt.de', 'braunschweiger-zeitung.de', 'morgenpost.de', 'nrz.de', 'otz.de', 'thueringer-allgemeine.de', 'tlz.de', 'waz.de', 'wp.de', 'wr.de'];
 var de_madsack_domains = ['haz.de', 'kn-online.de', 'ln-online.de', 'lvz.de', 'maz-online.de', 'neuepresse.de', 'ostsee-zeitung.de', 'rnd.de'];
-var de_madsack_custom_domains = ['dnn.de', 'gnz.de', 'goettinger-tageblatt.de', 'op-marburg.de', 'paz-online.de', 'siegener-zeitung.de', 'sn-online.de', 'waz-online.de'];
 var de_vrm_domains = ['allgemeine-zeitung.de', 'echo-online.de', 'wiesbadener-kurier.de'];
 var de_westfalen_medien_domains = ['muensterschezeitung.de', 'westfalen-blatt.de', 'wn.de'];
 var es_epiberica_domains = ['diariodemallorca.es', 'eldia.es', 'epe.es', 'farodevigo.es', 'informacion.es', 'laprovincia.es', 'levante-emv.com', 'lne.es', 'mallorcazeitung.es'];
@@ -975,7 +974,7 @@ else if (matchDomain(de_funke_medien_domains) || document.querySelector('a[href=
     sessionStorage.setItem('deobfuscate', 'true');
 }
 
-else if (matchDomain(de_madsack_domains) || matchDomain(de_madsack_custom_domains)) {
+else if (matchDomain(de_madsack_domains) || document.querySelector('link[href*=".rndtech.de/"]')) {
   // plus code in contentScript_once_var.js (timing)
   if (!window.location.search.startsWith('?outputType=valid_amp')) {
     let ads = document.querySelectorAll('div[class^="Adstyled__AdWrapper"]');
diff --git a/contentScript_once_var.js b/contentScript_once_var.js
index 4b1775f6..563d43f1 100644
--- a/contentScript_once_var.js
+++ b/contentScript_once_var.js
@@ -1,8 +1,10 @@
 //'use strict';
 var ext_api = (typeof browser === 'object') ? browser : chrome;
 
+var hostname = window.location.hostname;
 var de_madsack_domains = ['haz.de', 'kn-online.de', 'ln-online.de', 'lvz.de', 'maz-online.de', 'neuepresse.de', 'ostsee-zeitung.de', 'rnd.de'];
-var de_madsack_custom_domains = ['dnn.de', 'gnz.de', 'goettinger-tageblatt.de', 'op-marburg.de', 'paz-online.de', 'siegener-zeitung.de', 'sn-online.de', 'waz-online.de'];
+
+if (hostname.match(/\.de$/)) {
 
 if (matchDomain('cz.de')) {
   function cz_unhide(node) {
@@ -14,7 +16,7 @@ if (matchDomain('cz.de')) {
   waitDOMElement('div#erasmo', 'DIV', cz_unhide);
 }
 
-else if (matchDomain(de_madsack_domains) || matchDomain(de_madsack_custom_domains)) {
+else if (matchDomain(de_madsack_domains) || document.querySelector('link[href*=".rndtech.de/"]')) {
   function madsack_main() {
     let done = false;
     for (let n = 0; n < 10; n++) {
@@ -29,7 +31,7 @@ else if (matchDomain(de_madsack_domains) || matchDomain(de_madsack_custom_domain
   insert_script(madsack_main);
 }
 
-else if (matchDomain('nzherald.co.nz')) {
+} else if (matchDomain('nzherald.co.nz')) {
   function nzherald_main() {
     let done = false;
     for (let n = 0; n < 10; n++) {
diff --git a/custom/manifest.json b/custom/manifest.json
index ecc591a8..9ead9464 100644
--- a/custom/manifest.json
+++ b/custom/manifest.json
@@ -51,5 +51,5 @@
     "webRequestBlocking",
     "*://*/*"
   ],
-  "version": "3.0.6.3"
+  "version": "3.0.6.4"
 }
diff --git a/manifest.json b/manifest.json
index d68ea59f..a5365839 100644
--- a/manifest.json
+++ b/manifest.json
@@ -739,5 +739,5 @@
     "*://*.wallkit.net/*",
     "*://webcache.googleusercontent.com/*"
   ],
-  "version": "3.0.6.3"
+  "version": "3.0.6.4"
 }
diff --git a/sites.js b/sites.js
index 5fd3b2de..f079c094 100644
--- a/sites.js
+++ b/sites.js
@@ -2439,7 +2439,6 @@ expandSiteRules(defaultSites);
 // grouped domains (background)
 var au_news_corp_domains = grouped_sites['###_au_news_corp'];
 var de_madsack_domains = grouped_sites['###_de_madsack'];
-var de_madsack_custom_domains = ['dnn.de', 'gnz.de', 'goettinger-tageblatt.de', 'op-marburg.de', 'paz-online.de', 'siegener-zeitung.de', 'sn-online.de', 'waz-online.de'];
 var es_grupo_vocento_domains = grouped_sites['###_es_grupo_vocento'];
 var nl_mediahuis_region_domains = grouped_sites['###_nl_mediahuis_region'];
 var no_nhst_media_domains = grouped_sites['###_no_nhst_media'];