diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index 9ffd9c3bc..d3b38f9ee 100644
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -208,6 +208,7 @@ class Receiver
 
 		if (!$trust_source) {
 			logger('No trust for activity type "' . $activity['type'] . '", so we quit now.', LOGGER_DEBUG);
+			return;
 		}
 
 		switch ($activity['type']) {
diff --git a/src/Worker/Notifier.php b/src/Worker/Notifier.php
index d40d9068f..b57c81db7 100644
--- a/src/Worker/Notifier.php
+++ b/src/Worker/Notifier.php
@@ -20,6 +20,7 @@ use Friendica\Protocol\ActivityPub;
 use Friendica\Protocol\Diaspora;
 use Friendica\Protocol\OStatus;
 use Friendica\Protocol\Salmon;
+use Friendica\Model\Conversation;
 
 require_once 'include/dba.php';
 require_once 'include/items.php';
@@ -514,6 +515,12 @@ class Notifier
 
 		if ($target_item['origin']) {
 			$inboxes = ActivityPub\Transmitter::fetchTargetInboxes($target_item, $uid);
+			logger('Origin item ' . $item_id . ' with URL ' . $target_item['uri'] . ' will be distributed.', LOGGER_DEBUG);
+		} elseif (!DBA::exists('conversation', ['item-uri' => $target_item['uri'], 'protocol' => Conversation::PARCEL_ACTIVITYPUB])) {
+			logger('Remote item ' . $item_id . ' with URL ' . $target_item['uri'] . ' is no AP post. It will not be distributed.', LOGGER_DEBUG);
+			return;
+		} else {
+			logger('Remote item ' . $item_id . ' with URL ' . $target_item['uri'] . ' will be distributed.', LOGGER_DEBUG);
 		}
 
 		if ($parent['origin']) {
@@ -521,6 +528,11 @@ class Notifier
 			$inboxes = array_merge($inboxes, $parent_inboxes);
 		}
 
+		if (empty($inboxes)) {
+			logger('No inboxes found for item ' . $item_id . ' with URL ' . $target_item['uri'] . '. It will not be distributed.', LOGGER_DEBUG);
+			return;
+		}
+
 		// Fill the item cache
 		ActivityPub\Transmitter::createCachedActivityFromItem($item_id);