diff --git a/lib/Chat/ChatManager.php b/lib/Chat/ChatManager.php
index d59075c6e17..b709581ddc7 100644
--- a/lib/Chat/ChatManager.php
+++ b/lib/Chat/ChatManager.php
@@ -521,6 +521,8 @@ public function deleteMessage(Room $chat, IComment $comment, Participant $partic
 
 		$this->referenceManager->invalidateCache($chat->getToken());
 
+		$this->unreadCountCache->clear($chat->getId() . '-');
+
 		return $this->addSystemMessage(
 			$chat,
 			$participant->getAttendee()->getActorType(),