Fix check

AKModel/models.py

@@ -584,7 +584,7 @@ class Room(models.Model):
         #       event end + 1 day
         full_event = Availability(event=self.event, start=self.event.start, end=self.event.end)
         avail_union = Availability.union(self.availabilities.all())
-        if len(avail_union) == 1 and avail_union[0].contains(full_event):
+        if not avail_union or avail_union[0].contains(full_event):
             time_constraints = []
         else:
             time_constraints = [f"availability-room-{self.pk}"]