diff --git a/tempest/common/isolated_creds.py b/tempest/common/isolated_creds.py
index 228e47c..1ce1e39 100644
--- a/tempest/common/isolated_creds.py
+++ b/tempest/common/isolated_creds.py
@@ -203,9 +203,8 @@
                 if 'overlaps with another subnet' not in str(e):
                     raise
         else:
-            e = exceptions.BuildErrorException()
-            e.message = 'Available CIDR for subnet creation could not be found'
-            raise e
+            message = 'Available CIDR for subnet creation could not be found'
+            raise Exception(message)
         return resp_body['subnet']
 
     def _create_router(self, router_name, tenant_id):