diff --git a/letsencrypt-postfix/PostfixConfigGenerator.py b/letsencrypt-postfix/PostfixConfigGenerator.py
index 43a8fa116..214d98954 100755
--- a/letsencrypt-postfix/PostfixConfigGenerator.py
+++ b/letsencrypt-postfix/PostfixConfigGenerator.py
@@ -149,7 +149,7 @@ class PostfixConfigGenerator:
             if len(mx_list) > 1:
                 logger.warn('Lists of multiple accept-mx-domains not yet '
                             'supported.')
-                logger.warn('Using MX {} for {}".format(mx_list[0],
+                logger.warn('Using MX {} for {}'.format(mx_list[0],
                                                         address_domain)
                            )
                 logger.warn('Ignoring: {}'.format(', '.join(mx_list[1:])))