diff --git a/src/shrpx_downstream.cc b/src/shrpx_downstream.cc
index 2c983819..1fb46a0f 100644
--- a/src/shrpx_downstream.cc
+++ b/src/shrpx_downstream.cc
@@ -55,7 +55,7 @@ Downstream::Downstream(Upstream *upstream, int stream_id, int priority)
     stream_id_(stream_id),
     priority_(priority),
     downstream_stream_id_(-1),
-    response_rst_stream_error_code_(NGHTTP2_NO_ERROR),
+    response_rst_stream_error_code_(-1),
     request_state_(INITIAL),
     request_major_(1),
     request_minor_(1),
@@ -821,13 +821,12 @@ int32_t Downstream::get_downstream_stream_id() const
   return downstream_stream_id_;
 }
 
-nghttp2_error_code Downstream::get_response_rst_stream_error_code() const
+int Downstream::get_response_rst_stream_error_code() const
 {
   return response_rst_stream_error_code_;
 }
 
-void Downstream::set_response_rst_stream_error_code
-(nghttp2_error_code error_code)
+void Downstream::set_response_rst_stream_error_code(int error_code)
 {
   response_rst_stream_error_code_ = error_code;
 }
diff --git a/src/shrpx_downstream.h b/src/shrpx_downstream.h
index 490aa2e5..90a4b8bb 100644
--- a/src/shrpx_downstream.h
+++ b/src/shrpx_downstream.h
@@ -206,8 +206,8 @@ public:
   evbuffer* get_response_body_buf();
   void add_response_bodylen(size_t amount);
   int64_t get_response_bodylen() const;
-  nghttp2_error_code get_response_rst_stream_error_code() const;
-  void set_response_rst_stream_error_code(nghttp2_error_code error_code);
+  int get_response_rst_stream_error_code() const;
+  void set_response_rst_stream_error_code(int error_code);
   // Inspects HTTP/1 response.  This checks tranfer-encoding etc.
   void inspect_http1_response();
   // Clears some of member variables for response.
@@ -301,7 +301,7 @@ private:
   int32_t downstream_stream_id_;
 
   // RST_STREAM error_code from downstream HTTP2 connection
-  nghttp2_error_code response_rst_stream_error_code_;
+  int response_rst_stream_error_code_;
 
   int request_state_;
   int request_major_;
diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index 72fa85dd..fcd15108 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -626,14 +626,14 @@ int on_unknown_frame_recv_callback(nghttp2_session *session,
 
 namespace {
 nghttp2_error_code infer_upstream_rst_stream_error_code
-(nghttp2_error_code downstream_error_code)
+(int downstream_error_code)
 {
   // NGHTTP2_REFUSED_STREAM is important because it tells upstream
   // client to retry.
   switch(downstream_error_code) {
   case NGHTTP2_NO_ERROR:
   case NGHTTP2_REFUSED_STREAM:
-    return downstream_error_code;
+    return static_cast<nghttp2_error_code>(downstream_error_code);
   default:
     return NGHTTP2_INTERNAL_ERROR;
   }
diff --git a/src/shrpx_spdy_upstream.cc b/src/shrpx_spdy_upstream.cc
index b2bc1033..f5e35ef3 100644
--- a/src/shrpx_spdy_upstream.cc
+++ b/src/shrpx_spdy_upstream.cc
@@ -411,8 +411,7 @@ void on_unknown_ctrl_recv_callback(spdylay_session *session,
 namespace {
 // Infer upstream RST_STREAM status code from downstream HTTP/2
 // error code.
-uint32_t infer_upstream_rst_stream_status_code
-(nghttp2_error_code downstream_error_code)
+uint32_t infer_upstream_rst_stream_status_code(int downstream_error_code)
 {
   // Only propagate *_REFUSED_STREAM so that upstream client can
   // resend request.