diff --git a/tilecloud_chain/server.py b/tilecloud_chain/server.py
index 34307023d..021cd3d19 100644
--- a/tilecloud_chain/server.py
+++ b/tilecloud_chain/server.py
@@ -186,6 +186,7 @@ def get_s3_client(self, config: tilecloud_chain.DatedConfig) -> "botocore.client
                 self.s3_client_cache[cache_s3.get("host", "aws")] = client
                 return client
             except KeyError as e:
+                _LOGGER.warning("Error while getting the S3 client: %s", e, exc_info=True)
                 error = e
             time.sleep(n * 10)
         raise error