diff --git a/waku/store/v2beta4/store.proto b/waku/store/v2beta4/store.proto
index 27f9c3c..1a3422f 100644
--- a/waku/store/v2beta4/store.proto
+++ b/waku/store/v2beta4/store.proto
@@ -43,6 +43,8 @@ message HistoryResponse {
   enum Error {
     NONE = 0;
     INVALID_CURSOR = 1;
+    TOO_MANY_RESULTS = 429;
+    SERVICE_UNAVAILABLE = 503;
   }
   Error error = 4;
 }