diff --git a/src/main/java/org/gcube/gcat/api/configuration/CatalogueConfiguration.java b/src/main/java/org/gcube/gcat/api/configuration/CatalogueConfiguration.java
index 2155428..8acb552 100644
--- a/src/main/java/org/gcube/gcat/api/configuration/CatalogueConfiguration.java
+++ b/src/main/java/org/gcube/gcat/api/configuration/CatalogueConfiguration.java
@@ -1,5 +1,6 @@
 package org.gcube.gcat.api.configuration;
 
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
@@ -88,6 +89,8 @@ public class CatalogueConfiguration {
 		
 		this.moderationEnabled = false; // default is false
 		
+		additionalProperties = new HashMap<>();
+		
 	}
 	
 	public CatalogueConfiguration(String context) {