diff --git a/weboob/tools/capabilities/messages/GenericBackend.py b/weboob/tools/capabilities/messages/GenericBackend.py
index 254318ae..bbca756b 100644
--- a/weboob/tools/capabilities/messages/GenericBackend.py
+++ b/weboob/tools/capabilities/messages/GenericBackend.py
@@ -81,7 +81,7 @@ class GenericNewspaperBackend(BaseBackend, ICapMessages):
 
     def iter_unread_messages(self, thread=None):
         for thread in self.iter_threads():
-            self.fill_thread(thread)
+            self.fill_thread(thread, 'root')
             for msg in thread.iter_all_messages():
                 if msg.flags & msg.IS_UNREAD:
                     yield msg