diff --git a/config/mail.php b/config/mail.php
index 97f452356..10be8534c 100644
--- a/config/mail.php
+++ b/config/mail.php
@@ -93,11 +93,12 @@
     | Auth mode
     |--------------------------------------------------------------------------
     |
-    | 'login' or 'XOAUTH2'
+    | This option have an effect when set to 'XOAUTH2' only.
+    | In other cases Swiftmailer chooses auth mode automatically.
     |
     */
 
-    'auth_mode' => env('MAIL_AUTH_MODE', 'login'),
+    'auth_mode' => env('MAIL_AUTH_MODE', ''),
 
     /*
     |--------------------------------------------------------------------------
diff --git a/overrides/swiftmailer/swiftmailer/lib/classes/Swift/SmtpTransport.php b/overrides/swiftmailer/swiftmailer/lib/classes/Swift/SmtpTransport.php
index 9ec539c6f..3164e11a6 100644
--- a/overrides/swiftmailer/swiftmailer/lib/classes/Swift/SmtpTransport.php
+++ b/overrides/swiftmailer/swiftmailer/lib/classes/Swift/SmtpTransport.php
@@ -27,7 +27,7 @@ class Swift_SmtpTransport extends Swift_Transport_EsmtpTransport
      * @param int    $port
      * @param string $encryption
      */
-    public function __construct($host = 'localhost', $port = 25, $encryption = null, $auth_mode = 'login')
+    public function __construct($host = 'localhost', $port = 25, $encryption = null, $auth_mode = '')
     {
         parent::__construct(...Swift_DependencyContainer::getInstance()->createDependenciesFor('transport.smtp'));
         // call_user_func_array(
@@ -39,6 +39,8 @@ public function __construct($host = 'localhost', $port = 25, $encryption = null,
         $this->setHost($host);
         $this->setPort($port);
         $this->setEncryption($encryption);
-        $this->setAuthMode($auth_mode);
+        if ($auth_mode == 'XOAUTH2') {
+            $this->setAuthMode($auth_mode);
+        }
     }
 }