diff --git a/packaging/setup/plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py b/packaging/setup/plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py
index 512f6fa..75ef374 100644
--- a/packaging/setup/plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py
+++ b/packaging/setup/plugins/ovirt-engine-setup/ovirt-engine-grafana-dwh/core/config.py
@@ -220,7 +220,7 @@ def _customization_sso(self):
                 prompt=True,
                 default=True,
             )
-            with open(tmpconf, 'w') as f:
+            with open(tmpconf, 'wb') as f:
                 f.write(res)
             self._process_sso_client_registration_result(tmpconf)