diff --git a/src/Model/Item.php b/src/Model/Item.php
index 2db3d1d89..8cca6f693 100644
--- a/src/Model/Item.php
+++ b/src/Model/Item.php
@@ -1234,18 +1234,35 @@ class Item extends BaseObject
 
 	private static function contactId($item)
 	{
-		if (!empty($item['uid']) && !Contact::isSharing($item['author-id'], $item['uid'])) {
-			return $item['author-id'];
-		} elseif (!empty($item['contact-id'])) {
-			return $item['contact-id'];
-		} else {
+		$contact_id = (int)$item["contact-id"];
+
+		if (!empty($contact_id)) {
+			return $contact_id;
+		}
+		Logger::log('Missing contact-id. Called by: '.System::callstack(), Logger::DEBUG);
+		/*
+		 * First we are looking for a suitable contact that matches with the author of the post
+		 * This is done only for comments
+		 */
+		if ($item['parent-uri'] != $item['uri']) {
 			$contact_id = Contact::getIdForURL($item['author-link'], $item['uid']);
-			if (!empty($contact_id)) {
-				return $contact_id;
-			}
 		}
 
-		return $item['author-id'];
+		// If not present then maybe the owner was found
+		if ($contact_id == 0) {
+			$contact_id = Contact::getIdForURL($item['owner-link'], $item['uid']);
+		}
+
+		// Still missing? Then use the "self" contact of the current user
+		if ($contact_id == 0) {
+			$self = DBA::selectFirst('contact', ['id'], ['self' => true, 'uid' => $item['uid']]);
+			if (DBA::isResult($self)) {
+				$contact_id = $self["id"];
+			}
+		}
+		Logger::log("Contact-id was missing for post ".$item['guid']." from user id ".$item['uid']." - now set to ".$contact_id, Logger::DEBUG);
+
+		return $contact_id;
 	}
 
 	// This function will finally cover most of the preparation functionality in mod/item.php
@@ -1470,6 +1487,9 @@ class Item extends BaseObject
 
 		$item['plink'] = defaults($item, 'plink', System::baseUrl() . '/display/' . urlencode($item['guid']));
 
+		// The contact-id should be set before "self::insert" was called - but there seems to be issues sometimes
+		$item["contact-id"] = self::contactId($item);
+
 		$default = ['url' => $item['author-link'], 'name' => $item['author-name'],
 			'photo' => $item['author-avatar'], 'network' => $item['network']];
 
@@ -1525,9 +1545,6 @@ class Item extends BaseObject
 		unset($item['causer-id']);
 		unset($item['causer-link']);
 
-		// The contact-id should be set before "self::insert" was called - but there seems to be issues sometimes
-		$item['contact-id'] = self::contactId($item);
-
 		if ($item['network'] == Protocol::PHANTOM) {
 			$item['network'] = Protocol::DFRN;
 			Logger::notice('Missing network, setting to {network}.', [
diff --git a/src/Protocol/ActivityPub/Processor.php b/src/Protocol/ActivityPub/Processor.php
index 65dd6d3e6..7639d0f2a 100644
--- a/src/Protocol/ActivityPub/Processor.php
+++ b/src/Protocol/ActivityPub/Processor.php
@@ -419,8 +419,8 @@ class Processor
 				$item['contact-id'] = Contact::getIdForURL($activity['author'], $receiver, true);
 			}
 
-			if (empty($item['contact-id'])) {
-				$item['contact-id'] = $item['author-id'];
+			if (($receiver != 0) && empty($item['contact-id'])) {
+				$item['contact-id'] = Contact::getIdForURL($activity['author'], 0, true);
 			}
 
 			if (!empty($activity['directmessage'])) {