diff --git a/modules/Classes/UserCredentials.py b/modules/Classes/UserCredentials.py
index cbc9fcc..6ded7fa 100644
--- a/modules/Classes/UserCredentials.py
+++ b/modules/Classes/UserCredentials.py
@@ -41,4 +41,5 @@ class UserCredentials:
             debug("No new credentials.")
 
     def is_valid(self):
-        return self.current < self.total
+        return (self.current < self.total
+                and self.get_mail() != "" and self.get_mail is not None)