Fixes #67: If transport is gone, try to restart transport

CHANGELOG.md

@@ -5,7 +5,7 @@ Yii Framework 2 swiftmailer extension Change Log
 -----------------------
 
 - Enh #63: Added ability to specify the disposition of an attachment by supplying a `setDisposition` value when embedding content in a message (CorWatts)
-
+- Bug #67: If transport is gone, try to restart transport (mikk150)
 
 2.1.1 April 25, 2018
 --------------------

src/Mailer.php

@@ -133,6 +133,11 @@ class Mailer extends BaseMailer
             $this->_transport = $this->createTransport($this->_transport);
         }
 
+        if (!$this->_transport->ping()) {
+            $this->_transport->stop();
+            $this->_transport->start();
+        }
+
         return $this->_transport;
     }