diff --git a/flavours/classic/config/activity_pub.exs b/flavours/classic/config/activity_pub.exs
index db06c9cbea..ffc170c6fb 100755
--- a/flavours/classic/config/activity_pub.exs
+++ b/flavours/classic/config/activity_pub.exs
@@ -13,6 +13,8 @@ config :activity_pub, :instance,
   hostname: "localhost",
   federation_publisher_modules: [ActivityPub.Federator.APPublisher],
   federation_reachability_timeout_days: 7,
+  # Max. depth of reply-to and reply activities fetching on incoming federation, to prevent out-of-memory situations while fetching very long threads.
+  federation_incoming_max_recursion: 10,
   rewrite_policy: [Bonfire.Federate.ActivityPub.BoundariesMRF],
   handle_unknown_activities: true