diff --git a/cms/settings.py b/cms/settings.py
index 686092a6..19bb8438 100644
--- a/cms/settings.py
+++ b/cms/settings.py
@@ -416,7 +416,9 @@ CACHES = {
     }
 }
 
-SESSION_ENGINE = "django.contrib.sessions.backends.cache"
+# Use cached_db for reliability - stores in both cache AND database
+# This prevents session loss during multiple simultaneous LTI launches
+SESSION_ENGINE = "django.contrib.sessions.backends.cached_db"
 SESSION_CACHE_ALIAS = "default"
 
 # CELERY STUFF