diff --git a/ydb/core/kafka_proxy/actors/control_plane_common.h b/ydb/core/kafka_proxy/actors/control_plane_common.h
index 155ae184af83..1e78af96d832 100644
--- a/ydb/core/kafka_proxy/actors/control_plane_common.h
+++ b/ydb/core/kafka_proxy/actors/control_plane_common.h
@@ -30,7 +30,7 @@ struct TRetentionsConversionResult {
 
             TStringBuilder resultErrorMessage;
             resultErrorMessage << ErrorMessages[0];
-            for (ulong i = 1; i < ErrorMessages.size(); i++) {
+            for (ui64 i = 1; i < ErrorMessages.size(); i++) {
                 resultErrorMessage << ' ' << ErrorMessages[i];
             }
             response->Message = resultErrorMessage;