diff --git a/journal/views.py b/journal/views.py
index 78a19b74..8e35841d 100644
--- a/journal/views.py
+++ b/journal/views.py
@@ -151,9 +151,8 @@ def mark(request, item_uuid):
             )
             mark_date = None
             if request.POST.get("mark_anotherday"):
-                mark_date = timezone.get_current_timezone().localize(
-                    parse_datetime(request.POST.get("mark_date") + " 20:00:00")
-                )
+                dt = parse_datetime(request.POST.get("mark_date", "") + " 20:00:00")
+                mark_date = timezone.get_current_timezone().localize(dt) if dt else None
                 if mark_date and mark_date >= timezone.now():
                     mark_date = None
             TagManager.tag_item_by_user(item, request.user, tags, visibility)