# HG changeset patch
# User Benjamin Peterson <benjamin@python.org>
# Date 1465676202 25200
# Node ID b3ce713fb9beebfff9848cefa0acbd59acc68fe9
# Parent  3017e41b0c99d24e88faf1de447f230e2f64d122
raise an error when STARTTLS fails

diff --git a/Lib/smtplib.py b/Lib/smtplib.py
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -656,6 +656,11 @@ class SMTP:
             self.ehlo_resp = None
             self.esmtp_features = {}
             self.does_esmtp = 0
+        else:
+            # RFC 3207:
+            # 501 Syntax error (no parameters allowed)
+            # 454 TLS not available due to temporary reason
+            raise SMTPResponseException(resp, reply)
         return (resp, reply)
 
     def sendmail(self, from_addr, to_addrs, msg, mail_options=[],