diff --git a/pool-server.go b/pool-server.go
index 4b46f40..ac3b52e 100644
--- a/pool-server.go
+++ b/pool-server.go
@@ -56,7 +56,11 @@ func (s *PoolServer) WriteResult(w http.ResponseWriter, result *CallResult) erro
 	w.Header().Set("Content-Type", "application/json")
 	w.Header().Set("X-Pod-Name", s.pod_name)
 	if result.StatusCode != 200 {
-		w.WriteHeader(int(result.StatusCode))
+		if result.StatusCode > 299 && result.StatusCode < 499 {
+			w.WriteHeader(int(result.StatusCode))
+		} else {
+			w.WriteHeader(http.StatusInternalServerError)
+		}
 		w.Write([]byte(result.Data))
 		return nil
 	}