diff --git a/proto/protobuf/rpc/error.proto b/proto/protobuf/rpc/error.proto
index d30edf6..e3039c9 100644
--- a/proto/protobuf/rpc/error.proto
+++ b/proto/protobuf/rpc/error.proto
@@ -17,16 +17,17 @@ message Error {
 }
 
 enum InvalidParamsType {
-  DATE_TIME = 0;
-  DECIMAL = 1;
-  EQUALS_TO = 2;
-  FLOAT = 3;
-  INTEGER = 4;
-  RANGE = 5;
-  REG_EX = 6;
-  REQUIRED = 7;
-  STRING_LENGTH = 8;
-  URL = 9;
+  NONE = 0;
+  DATE_TIME = 1;
+  DECIMAL = 2;
+  EQUALS_TO = 3;
+  FLOAT = 4;
+  INTEGER = 5;
+  RANGE = 6;
+  REG_EX = 7;
+  REQUIRED = 8;
+  STRING_LENGTH = 9;
+  URL = 10;
 }
 
 message InvalidParamsDetail {