diff --git a/app.py b/app.py
index d55a6f9..35237fd 100644
--- a/app.py
+++ b/app.py
@@ -19,7 +19,7 @@ import logging
 import smtplib
 from email.mime.text import MIMEText
 from email.header import Header
-from email.utils import formataddr
+from email.utils import formataddr, formatdate
 from datetime import datetime, date
 from pathlib import Path
 import sys
@@ -140,6 +140,7 @@ def send_email(subject, body, cfg=None, html=False):
 
     msg = MIMEText(body, 'html' if html else 'plain', 'utf-8')
     msg['Subject'] = Header(subject, 'utf-8')
+    msg['Date'] = formatdate(localtime=True)  # 必须带 Date 头，否则 mail.tphai.com 的 amavisd 会拒收(554 BAD HEADER)
     from_addr = cfg.get('from_addr') or cfg.get('smtp_user') or ''
     msg['From'] = formataddr((str(Header(cfg.get('from_name', ''), 'utf-8')), from_addr))
     msg['To'] = ', '.join(to_addrs)