diff --git a/app/boxes.py b/app/boxes.py
index 9e2123c..adcfc0f 100644
--- a/app/boxes.py
+++ b/app/boxes.py
@@ -439,7 +439,9 @@ async def _send_undo(db_session: AsyncSession, ap_object_id: str) -> None:
         announced_object.announced_via_outbox_object_ap_id = None
 
         # Send the Undo to the original recipients
-        recipients = await _compute_recipients(db_session, outbox_object.ap_object)
+        recipients = await _compute_recipients(
+            db_session, outbox_object_to_undo.ap_object
+        )
         for rcp in recipients:
             await new_outgoing_activity(db_session, rcp, outbox_object.id)
     elif outbox_object_to_undo.ap_type == "Block":