diff --git a/src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillSmtpTransport.php b/src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillSmtpTransport.php
index 72d2e8a51a..fee4d4a1de 100644
--- a/src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillSmtpTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Mailchimp/Transport/MandrillSmtpTransport.php
@@ -22,7 +22,7 @@ class MandrillSmtpTransport extends EsmtpTransport
 {
     public function __construct(string $username, string $password, EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)
     {
-        parent::__construct('smtp.mandrillapp.com', 587, true, $dispatcher, $logger);
+        parent::__construct('smtp.mandrillapp.com', 587, false, $dispatcher, $logger);
 
         $this->setUsername($username);
         $this->setPassword($password);
diff --git a/src/Symfony/Component/Mailer/Bridge/Postmark/Transport/PostmarkSmtpTransport.php b/src/Symfony/Component/Mailer/Bridge/Postmark/Transport/PostmarkSmtpTransport.php
index b6d9ba2827..bd955934b0 100644
--- a/src/Symfony/Component/Mailer/Bridge/Postmark/Transport/PostmarkSmtpTransport.php
+++ b/src/Symfony/Component/Mailer/Bridge/Postmark/Transport/PostmarkSmtpTransport.php
@@ -26,7 +26,7 @@ class PostmarkSmtpTransport extends EsmtpTransport
 {
     public function __construct(string $id, EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)
     {
-        parent::__construct('smtp.postmarkapp.com', 587, true, $dispatcher, $logger);
+        parent::__construct('smtp.postmarkapp.com', 587, false, $dispatcher, $logger);
 
         $this->setUsername($id);
         $this->setPassword($id);