plugin XEP-0277: fix unawaited coroutine.

libervia/backend/plugins/plugin_xep_0277.py

@@ -906,8 +906,13 @@ class XEP_0277:
         for item in itemsEvent.items:
             if item.name == C.PS_ITEM:
                 # FIXME: service and node should be used here
-                self.item_2_mb_data(client, item, None, None).addCallbacks(
-                    manage_item, lambda failure: None, (C.PS_PUBLISH,)
+                d = defer.ensureDeferred(self.item_2_mb_data(client, item, None, None))
+                d.addCallbacks(
+                    manage_item,
+                    lambda failure_: log.error(
+                        f"Can't convert the item {item['id']}: {failure_}"
+                    ),
+                    (C.PS_PUBLISH,),
                 )
             elif item.name == C.PS_RETRACT:
                 manage_item({"id": item["id"]}, C.PS_RETRACT)