diff --git a/edml/core/server.py b/edml/core/server.py
index bd5628a72401fd449f05f3430904b626d9970b9e..bc6ac5b2ede8ecbe86e40129b27d686cc1a3a33e 100644
--- a/edml/core/server.py
+++ b/edml/core/server.py
@@ -316,7 +316,7 @@ class DeviceServer:
                 executor.submit(
                     client_backpropagation_job, client_id, client_gradients[idx]
                 )
-                for (client_id, idx) in enumerate(client_ids)
+                for (idx, client_id) in enumerate(client_ids)
             ]
             client_backpropagation_results = []
             for future in concurrent.futures.as_completed(futures):