diff --git a/lib/Db/ChatMapper.php b/lib/Db/ChatMapper.php
index 99425e6..2ca1051 100644
--- a/lib/Db/ChatMapper.php
+++ b/lib/Db/ChatMapper.php
@@ -44,7 +44,7 @@ class ChatMapper extends QBMapper
 			->from('upschooling_chats')
 			->where(
 				$qb->expr()->eq('ticket_id', $qb->createNamedParameter($ticketId, IQueryBuilder::PARAM_INT)),
-				$qb->expr()->isNull('end_date')
+				$qb->expr()->isNull('date_end')
 			);
 		return $this->findEntity($qb);
 	}