diff --git a/src/server/cluster/cluster_family.cc b/src/server/cluster/cluster_family.cc
index db6d41bd5c03..b76cb5ab404c 100644
--- a/src/server/cluster/cluster_family.cc
+++ b/src/server/cluster/cluster_family.cc
@@ -1012,7 +1012,7 @@ void ClusterFamily::DflyMigrateAck(CmdArgList args, SinkReplyBuilder* builder) {
                    [source_id = source_id](const auto& m) { return m.node_info.id == source_id; });
   if (m_it == in_migrations.end()) {
     LOG(WARNING) << "migration isn't in config";
-    return builder->SendLong(OutgoingMigration::kInvalidAttempt);
+    return builder->SendError(OutgoingMigration::kUnknownMigration);
   }
 
   auto migration = GetIncomingMigration(source_id);
diff --git a/src/server/cluster/outgoing_slot_migration.h b/src/server/cluster/outgoing_slot_migration.h
index d1ce69f15143..eda8ef441927 100644
--- a/src/server/cluster/outgoing_slot_migration.h
+++ b/src/server/cluster/outgoing_slot_migration.h
@@ -59,7 +59,6 @@ class OutgoingMigration : private ProtocolClient {
 
   size_t GetKeyCount() const ABSL_LOCKS_EXCLUDED(state_mu_);
 
-  static constexpr long kInvalidAttempt = -1;
   static constexpr std::string_view kUnknownMigration = "UNKNOWN_MIGRATION";
 
  private: