diff --git a/aleksis/apps/chronos/util/build.py b/aleksis/apps/chronos/util/build.py
index 5a8ebfe8e38dc55345b84f209a6f664aa4e5da57..6b3668cb1689d2081c1b0a362c2136f1ed829976 100644
--- a/aleksis/apps/chronos/util/build.py
+++ b/aleksis/apps/chronos/util/build.py
@@ -53,6 +53,9 @@ def build_timetable(
         is_person = True
         type_ = obj.timetable_type
 
+    if type_ is None:
+        return None
+
     # Get matching holidays
     if is_person:
         holiday = Holiday.on_day(date_ref)