diff --git a/kleinanzeigen_bot/__init__.py b/kleinanzeigen_bot/__init__.py
index b20aaed..fd6d03e 100644
--- a/kleinanzeigen_bot/__init__.py
+++ b/kleinanzeigen_bot/__init__.py
@@ -175,6 +175,8 @@ class KleinanzeigenBot(SeleniumMixin):
                     last_updated_on = datetime.fromisoformat(ad_cfg["updated_on"])
                 elif ad_cfg["created_on"]:
                     last_updated_on = datetime.fromisoformat(ad_cfg["created_on"])
+                else:
+                    last_updated_on = None
 
                 if last_updated_on:
                     ad_age = datetime.utcnow() - last_updated_on