diff --git a/program/services.py b/program/services.py
index 4b0413c34a3c6490684f54ed0fe0e69bec261de6..eeb6ce3da8b77a2e32e5b3370a967765700489a2 100644
--- a/program/services.py
+++ b/program/services.py
@@ -847,6 +847,9 @@ def get_timerange_timeslot_entries(
     if not include_virtual:
         return [make_timeslot_entry(timeslot=timeslot) for timeslot in timeslots]
 
+    if timeslots is None:
+        return []
+
     timeslot_entries = []
     # gap before the first timeslot
     first_timeslot = timeslots.first()