diff --git a/sat/plugins/plugin_xep_0329.py b/sat/plugins/plugin_xep_0329.py
index 6971e0bb..0cb355af 100644
--- a/sat/plugins/plugin_xep_0329.py
+++ b/sat/plugins/plugin_xep_0329.py
@@ -827,6 +827,12 @@ class XEP_0329(object):
             peer_jid, owner = self._compParseJids(client, iq_elt)
             is_owner = peer_jid.userhostJID() == owner
             affiliations = {owner: 'owner'}
+        except exceptions.NotFound:
+            client.sendError(iq_elt, "item-not-found")
+            return
+        except Exception as e:
+            client.sendError(iq_elt, "internal-server-error", str(e))
+            return
         else:
             from_jid_bare = from_jid.userhostJID()
             is_owner = from_jid_bare == file_data.get('owner')