diff --git a/sinch/core/clients/sinch_client_configuration.py b/sinch/core/clients/sinch_client_configuration.py
index 06b3024..1af0f75 100644
--- a/sinch/core/clients/sinch_client_configuration.py
+++ b/sinch/core/clients/sinch_client_configuration.py
@@ -119,7 +119,7 @@ def _set_sms_domain(self, domain):
         self._set_sms_origin()
 
     def _get_sms_domain(self):
-        return self.sms_domain
+        return self._sms_domain
 
     sms_domain = property(
         _get_sms_domain,