diff --git a/hubzilla/addon/scn01/scn01_spool.php b/hubzilla/addon/scn01/scn01_spool.php
index 55e5199..82a8c24 100644
--- a/hubzilla/addon/scn01/scn01_spool.php
+++ b/hubzilla/addon/scn01/scn01_spool.php
@@ -140,7 +140,8 @@ function scn01_get_participant_id() {
 
     $addr  = $r[0]['xchan_addr'] ?? '';
     $parts = explode('@', $addr);
-    return $parts[0] ?? '';
+    // Strip guest: prefix — Placekey is the channel name without the guest: qualifier.
+    return preg_replace('/^guest:/', '', $parts[0] ?? '');
 }
 
 // ---------------------------------------------------------------------------