diff --git a/core/common/src/main/java/org/onosproject/codec/impl/GroupCodec.java b/core/common/src/main/java/org/onosproject/codec/impl/GroupCodec.java
index fa98d66..385f399 100644
--- a/core/common/src/main/java/org/onosproject/codec/impl/GroupCodec.java
+++ b/core/common/src/main/java/org/onosproject/codec/impl/GroupCodec.java
@@ -151,8 +151,7 @@
                 groupType = Group.Type.FAILOVER;
                 break;
             default:
-                log.warn("The requested type {} is not defined for group.", type);
-                return null;
+                nullIsIllegal(groupType, "The requested group type " + type + " is not valid");
         }
 
         // parse group buckets