diff --git a/radicale/app/__init__.py b/radicale/app/__init__.py
index eabac455..7f8301f2 100644
--- a/radicale/app/__init__.py
+++ b/radicale/app/__init__.py
@@ -269,7 +269,7 @@ class Application(ApplicationPartDelete, ApplicationPartHead,
             # Random delay to avoid timing oracles and bruteforce attacks
             if self._auth_delay > 0:
                 random_delay = self._auth_delay * (0.5 + random.random())
-                logger.debug("Sleeping %.3f seconds", random_delay)
+                logger.debug("Failed login, sleeping random: %.3f sec", random_delay)
                 time.sleep(random_delay)
 
         if user and not pathutils.is_safe_path_component(user):