diff --git a/target_salesforce_v3/client.py b/target_salesforce_v3/client.py
index 4209905..9e90742 100644
--- a/target_salesforce_v3/client.py
+++ b/target_salesforce_v3/client.py
@@ -192,8 +192,7 @@ def url(self, endpoint=None):
             endpoint = self.endpoint
         instance_url = self.config.get("instance_url")
         if not instance_url:
-            self.authenticator
-            instance_url = self.authenticator.instance_url
+            raise Exception("instance_url not defined in config")
         return f"{instance_url}/services/data/{self.api_version}/{endpoint}"
 
     def validate_input(self, record: dict):