diff --git a/src/api/controllers/batch-controller.js b/src/api/controllers/batch-controller.js
index 8b4b3e9..cd9734d 100644
--- a/src/api/controllers/batch-controller.js
+++ b/src/api/controllers/batch-controller.js
@@ -69,6 +69,9 @@ async function buildMergedPdf(subs) {
 async function ftpUpload(dateien) {
   const { host, port, user, password, secure, rejectUnauthorized } = config.ftp;
   if (!host || !user) throw new Error('FTP nicht konfiguriert (SKRIFT_FTP_HOST/USER fehlen).');
+  // Diagnose ohne Passwort-Leak: bei „530 Login incorrect" trotz korrekter Daten
+  // ist meist die Passwort-Laenge im .env falsch (Quotes/CRLF/Leerzeichen).
+  console.log(`[batch] FTP-Login: host=${host}:${port} user="${user}" pw_len=${(password || '').length} secure=${secure}`);
   const client = new ftp.Client(30000);
   // client.ftp.verbose = true;
   try {