diff --git a/src/service/clmcservice/aggregationapi/utilities.py b/src/service/clmcservice/aggregationapi/utilities.py
index 4a54b29b7281c657377f342f8c3c1a0a17baec84..bc55125cfcb5bc29476f2dfc6376031c54df3801 100644
--- a/src/service/clmcservice/aggregationapi/utilities.py
+++ b/src/service/clmcservice/aggregationapi/utilities.py
@@ -73,7 +73,7 @@ def validate_config_content(configuration):
     except:
         raise AssertionError("Configuration must be a JSON object.")
 
-    assert len(configuration) == len(CONFIG_ATTRIBUTES), "Configuration mustn't contain more attributes than the required ones."
+    assert len(configuration) == len(CONFIG_ATTRIBUTES), "Configuration mustn't contain a different number of attributes than the number of required ones."
 
     for attribute in CONFIG_ATTRIBUTES:
         assert attribute in configuration, "Required attribute not found in the request content."