diff --git a/lib/pleroma/web/ostatus/activity_representer.ex b/lib/pleroma/web/ostatus/activity_representer.ex
index 4f1976e1e..26d02a831 100644
--- a/lib/pleroma/web/ostatus/activity_representer.ex
+++ b/lib/pleroma/web/ostatus/activity_representer.ex
@@ -271,8 +271,7 @@ def to_simple_form(%{data: %{"type" => "Undo"}} = activity, user, with_author) d
            []}
         ] ++ mentions ++ author
 
-      _ ->
-        nil
+      _ -> []
     end
   end