diff --git a/lib/Db/NotesRequest.php b/lib/Db/NotesRequest.php
index 8d2a6ea1..2bf2ef77 100644
--- a/lib/Db/NotesRequest.php
+++ b/lib/Db/NotesRequest.php
@@ -133,7 +133,7 @@ class NotesRequest extends NotesRequestBuilder {
 		$cursor->closeCursor();
 
 		if ($data === false) {
-			throw new NoteNotFoundException();
+			throw new NoteNotFoundException('Post not found');
 		}
 
 		return $this->parseNotesSelectSql($data);
diff --git a/lib/Model/ActivityPub/ACore.php b/lib/Model/ActivityPub/ACore.php
index 1790718b..e0967c9c 100644
--- a/lib/Model/ActivityPub/ACore.php
+++ b/lib/Model/ActivityPub/ACore.php
@@ -538,13 +538,20 @@ abstract class ACore extends Item implements JsonSerializable {
 	 * @return array
 	 */
 	public function jsonSerialize(): array {
-		$context = [self::CONTEXT_ACTIVITYSTREAMS];
+
 		if ($this->gotSignature()) {
 			$this->entries['signature'] = $this->getSignature();
-			array_push($context, self::CONTEXT_SECURITY);
 		}
 
 		if ($this->isRoot()) {
+			$context = [self::CONTEXT_ACTIVITYSTREAMS];
+
+			if ($this->gotObject()
+				&& $this->getObject()
+						->gotSignature()) {
+				array_push($context, self::CONTEXT_SECURITY);
+			}
+
 			$this->addEntryArray('@context', $context);
 		}
 
diff --git a/lib/Model/ActivityPub/Note.php b/lib/Model/ActivityPub/Note.php
index 7598305e..03345ac3 100644
--- a/lib/Model/ActivityPub/Note.php
+++ b/lib/Model/ActivityPub/Note.php
@@ -32,6 +32,7 @@ namespace OCA\Social\Model\ActivityPub;
 
 use DateTime;
 use JsonSerializable;
+use OCA\Social\Exceptions\InvalidResourceEntryException;
 use OCA\Social\Service\ActivityService;
 
 class Note extends ACore implements JsonSerializable {
@@ -195,6 +196,8 @@ class Note extends ACore implements JsonSerializable {
 
 	/**
 	 * @param array $data
+	 *
+	 * @throws InvalidResourceEntryException
 	 */
 	public function import(array $data) {
 		parent::import($data);
diff --git a/lib/Service/ActivityPub/NoteService.php b/lib/Service/ActivityPub/NoteService.php
index af0257f9..98ae3552 100644
--- a/lib/Service/ActivityPub/NoteService.php
+++ b/lib/Service/ActivityPub/NoteService.php
@@ -31,14 +31,18 @@ declare(strict_types=1);
 namespace OCA\Social\Service\ActivityPub;
 
 
+use daita\MySmallPhpTools\Exceptions\MalformedArrayException;
 use Exception;
 use OC\User\NoUserException;
 use OCA\Social\Db\NotesRequest;
 use OCA\Social\Exceptions\ActorDoesNotExistException;
 use OCA\Social\Exceptions\InvalidOriginException;
+use OCA\Social\Exceptions\InvalidResourceException;
 use OCA\Social\Exceptions\NoteNotFoundException;
+use OCA\Social\Exceptions\Request410Exception;
 use OCA\Social\Exceptions\RequestException;
 use OCA\Social\Exceptions\SocialAppConfigException;
+use OCA\Social\Exceptions\UrlCloudException;
 use OCA\Social\Model\ActivityPub\ACore;
 use OCA\Social\Model\ActivityPub\Activity\Create;
 use OCA\Social\Model\ActivityPub\Note;
@@ -258,16 +262,27 @@ class NoteService implements ICoreService {
 	/**
 	 * @param Note $note
 	 * @param string $replyTo
+	 *
+	 * @throws InvalidResourceException
+	 * @throws MalformedArrayException
+	 * @throws NoteNotFoundException
+	 * @throws Request410Exception
+	 * @throws RequestException
+	 * @throws SocialAppConfigException
+	 * @throws UrlCloudException
 	 */
 	public function replyTo(Note $note, string $replyTo) {
 		if ($replyTo === '') {
 			return;
 		}
 
+		$author = $this->getAuthorFromPostId($replyTo);
 		$note->setInReplyTo($replyTo);
 		// TODO - type can be NOT public !
 		$note->addInstancePath(
-			new InstancePath($replyTo, InstancePath::TYPE_PUBLIC, InstancePath::PRIORITY_HIGH)
+			new InstancePath(
+				$author->getSharedInbox(), InstancePath::TYPE_INBOX, InstancePath::PRIORITY_HIGH
+			)
 		);
 	}
 
@@ -417,5 +432,23 @@ class NoteService implements ICoreService {
 		return $this->notesRequest->getStreamTimeline($since, $limit, false);
 	}
 
+
+	/**
+	 * @param $noteId
+	 *
+	 * @return Person
+	 * @throws NoteNotFoundException
+	 * @throws RequestException
+	 * @throws SocialAppConfigException
+	 * @throws InvalidResourceException
+	 * @throws Request410Exception
+	 * @throws UrlCloudException
+	 * @throws MalformedArrayException
+	 */
+	public function getAuthorFromPostId($noteId) {
+		$note = $this->notesRequest->getNoteById($noteId);
+
+		return $this->personService->getFromId($note->getAttributedTo());
+	}
 }
 
diff --git a/lib/Service/ActivityService.php b/lib/Service/ActivityService.php
index 37b3481a..dbacd1fc 100644
--- a/lib/Service/ActivityService.php
+++ b/lib/Service/ActivityService.php
@@ -159,6 +159,7 @@ class ActivityService {
 	public function createActivity(Person $actor, ACore $item, ACore &$activity = null): string {
 
 		$activity = new Create();
+		$item->setParent($activity);
 
 //		$this->activityStreamsService->initCore($activity);
 		$this->signObject($actor, $item);