diff --git a/proto/protobuf/rpc/error.proto b/proto/protobuf/rpc/error.proto
index cd8bcea..d30edf6 100644
--- a/proto/protobuf/rpc/error.proto
+++ b/proto/protobuf/rpc/error.proto
@@ -12,7 +12,7 @@ option go_package = "bet.com/protobuf/rpc";
 
 message Error {
   int32 code = 1;
-  optional string message = 2;
+  string message = 2;
   optional bytes data = 3;
 }