diff --git a/luigi/server.py b/luigi/server.py
index a10d668dbc..974e3f2cf8 100644
--- a/luigi/server.py
+++ b/luigi/server.py
@@ -266,8 +266,9 @@ def get(self, id):
 
 class ByTaskIdHandler(BaseTaskHistoryHandler):
     def get(self, task_id):
-        task = self._scheduler.task_history.find_task_by_task_id(task_id)
-        self.render("show.html", task=task)
+        with self._scheduler.task_history._session(None) as session:
+            task = self._scheduler.task_history.find_task_by_task_id(task_id, session)
+            self.render("show.html", task=task)
 
 
 class ByParamsHandler(BaseTaskHistoryHandler):