diff --git a/src/Model/Contact.php b/src/Model/Contact.php
index 1c90d0c815..6d435c81c0 100644
--- a/src/Model/Contact.php
+++ b/src/Model/Contact.php
@@ -1285,10 +1285,15 @@ class Contact extends BaseObject
 			return false;
 		}
 
-		$blocked = DBA::selectFirst('contact', ['blocked'], ['id' => $cid]);
+		$blocked = DBA::selectFirst('contact', ['blocked', 'url'], ['id' => $cid]);
 		if (!DBA::isResult($blocked)) {
 			return false;
 		}
+
+		if (Network::isUrlBlocked($blocked['url'])) {
+			return true;
+		}
+
 		return (bool) $blocked['blocked'];
 	}
 
diff --git a/src/Protocol/ActivityPub/Transmitter.php b/src/Protocol/ActivityPub/Transmitter.php
index 64b98e17e7..22c8a3518e 100644
--- a/src/Protocol/ActivityPub/Transmitter.php
+++ b/src/Protocol/ActivityPub/Transmitter.php
@@ -27,6 +27,7 @@ use Friendica\Protocol\ActivityPub;
 use Friendica\Protocol\Diaspora;
 use Friendica\Core\Cache;
 use Friendica\Util\Map;
+use Friendica\Util\Network;
 
 require_once 'include/api.php';
 
@@ -446,6 +447,10 @@ class Transmitter
 
 		$contacts = DBA::select('contact', ['url'], $condition);
 		while ($contact = DBA::fetch($contacts)) {
+			if (Network::isUrlBlocked($contact['url'])) {
+				continue;
+			}
+
 			$profile = APContact::getByURL($contact['url'], false);
 			if (!empty($profile)) {
 				if (empty($profile['sharedinbox']) || $personal) {
@@ -493,6 +498,10 @@ class Transmitter
 			$blindcopy = in_array($element, ['bto', 'bcc']);
 
 			foreach ($permissions[$element] as $receiver) {
+				if (Network::isUrlBlocked($receiver)) {
+					continue;
+				}
+
 				if ($receiver == $item_profile['followers']) {
 					$inboxes = array_merge($inboxes, self::fetchTargetInboxesforUser($uid, $personal));
 				} else {
diff --git a/src/Worker/Delivery.php b/src/Worker/Delivery.php
index 3ae0be140d..0d56bfa5d1 100644
--- a/src/Worker/Delivery.php
+++ b/src/Worker/Delivery.php
@@ -19,6 +19,7 @@ use Friendica\Protocol\DFRN;
 use Friendica\Protocol\Diaspora;
 use Friendica\Protocol\Email;
 use Friendica\Util\Strings;
+use Friendica\Util\Network;
 
 require_once 'include/items.php';
 
@@ -158,6 +159,10 @@ class Delivery extends BaseObject
 			return;
 		}
 
+		if (Network::isUrlBlocked($contact['url'])) {
+			return;
+		}
+
 		// Transmit via Diaspora if the thread had started as Diaspora post
 		// This is done since the uri wouldn't match (Diaspora doesn't transmit it)
 		if (isset($parent) && ($parent['network'] == Protocol::DIASPORA) && ($contact['network'] == Protocol::DFRN)) {