diff --git a/core/admin/mailu/internal/nginx.py b/core/admin/mailu/internal/nginx.py
index 420fe252..90b59712 100644
--- a/core/admin/mailu/internal/nginx.py
+++ b/core/admin/mailu/internal/nginx.py
@@ -24,7 +24,8 @@ STATUSES = {
         "imap": "LIMIT",
         "smtp": "451 4.3.2",
         "submission": "451 4.3.2",
-        "pop3": "-ERR [LOGIN-DELAY] Retry later"
+        "pop3": "-ERR [LOGIN-DELAY] Retry later",
+        "sieve": "AuthFailed"
     }),
 }