diff --git a/src/protobuf/rpc.rs b/src/protobuf/rpc.rs
index 744ce52..83c69d3 100644
--- a/src/protobuf/rpc.rs
+++ b/src/protobuf/rpc.rs
@@ -3,8 +3,8 @@ use std::fmt;
 pub struct Error {
   #[prost(int32, tag = "1")]
   pub code: i32,
-  #[prost(string, optional, tag = "2")]
-  pub message: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "2")]
+  pub message: ::prost::alloc::string::String,
   #[prost(bytes = "vec", optional, tag = "3")]
   pub data: ::core::option::Option<::prost::alloc::vec::Vec<u8>>,
 }