diff --git a/radicale/auth/htpasswd.py b/radicale/auth/htpasswd.py
index 1f6c3865..57bf1a40 100644
--- a/radicale/auth/htpasswd.py
+++ b/radicale/auth/htpasswd.py
@@ -282,5 +282,7 @@ class Auth(auth.BaseAuth):
             else:
                 logger.debug("Login verification failed for user: '%s' ( method '%s')", login, method)
         else:
+            # dummy delay
+            (method, password_ok) = self._plain(str(htpasswd_mtime_ns), password)
             logger.debug("Login verification user not found: '%s'", login)
         return ""