diff --git a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/EntityManagement.java b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/EntityManagement.java
index d499e63..de565d5 100644
--- a/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/EntityManagement.java
+++ b/src/main/java/org/gcube/informationsystem/resourceregistry/instances/model/entities/EntityManagement.java
@@ -541,7 +541,7 @@ public abstract class EntityManagement<E extends Entity, ET extends EntityType>
 			try {
 				element = ElementManagementUtility.getAnyElementByUUID(oDatabaseDocument, referenceUUID);
 			}catch (ResourceRegistryException e) {
-				String error = String.format("No instace with UUID % exists", referenceUUID);
+				String error = String.format("No instace with UUID %s exists", referenceUUID.toString());
 				throw new InvalidQueryException(error);
 			}