diff --git a/src/Symfony/Component/Mailer/Tests/TransportTest.php b/src/Symfony/Component/Mailer/Tests/TransportTest.php
index 4ecec2e66a..0d1f143262 100644
--- a/src/Symfony/Component/Mailer/Tests/TransportTest.php
+++ b/src/Symfony/Component/Mailer/Tests/TransportTest.php
@@ -236,9 +236,11 @@ class TransportTest extends TestCase
 
     public function testFromDsnFailover()
     {
+        $user = 'user';
+        $pass = 'pass';
         $dispatcher = $this->createMock(EventDispatcherInterface::class);
         $logger = $this->createMock(LoggerInterface::class);
-        $transport = Transport::fromDsn('smtp://null || smtp://null || smtp://null', $dispatcher, null, $logger);
+        $transport = Transport::fromDsn('smtp://example.com || smtp://'.urlencode($user).'@example.com || smtp://'.urlencode($user).':'.urlencode($pass).'@example.com', $dispatcher, null, $logger);
         $this->assertInstanceOf(Transport\FailoverTransport::class, $transport);
         $p = new \ReflectionProperty(Transport\RoundRobinTransport::class, 'transports');
         $p->setAccessible(true);
@@ -247,6 +249,12 @@ class TransportTest extends TestCase
         foreach ($transports as $transport) {
             $this->assertProperties($transport, $dispatcher, $logger);
         }
+        $this->assertSame('', $transports[0]->getUsername());
+        $this->assertSame('', $transports[0]->getPassword());
+        $this->assertSame($user, $transports[1]->getUsername());
+        $this->assertSame('', $transports[1]->getPassword());
+        $this->assertSame($user, $transports[2]->getUsername());
+        $this->assertSame($pass, $transports[2]->getPassword());
     }
 
     public function testFromDsnRoundRobin()
diff --git a/src/Symfony/Component/Mailer/Transport.php b/src/Symfony/Component/Mailer/Transport.php
index f5202242a3..eeb1892fe8 100644
--- a/src/Symfony/Component/Mailer/Transport.php
+++ b/src/Symfony/Component/Mailer/Transport.php
@@ -171,7 +171,17 @@ class Transport
                 throw new LogicException(sprintf('The "%s" scheme is not supported for mailer "%s".', $parsedDsn['scheme'], $parsedDsn['host']));
             default:
                 if ('smtp' === $parsedDsn['scheme']) {
-                    return new Transport\Smtp\EsmtpTransport($parsedDsn['host'], $parsedDsn['port'] ?? 25, $query['encryption'] ?? null, $query['auth_mode'] ?? null, $dispatcher, $logger);
+                    $transport = new Transport\Smtp\EsmtpTransport($parsedDsn['host'], $parsedDsn['port'] ?? 25, $query['encryption'] ?? null, $query['auth_mode'] ?? null, $dispatcher, $logger);
+
+                    if ($user) {
+                        $transport->setUsername($user);
+                    }
+
+                    if ($pass) {
+                        $transport->setPassword($pass);
+                    }
+
+                    return $transport;
                 }
 
                 throw new LogicException(sprintf('The "%s" mailer is not supported.', $parsedDsn['host']));
diff --git a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
index fc0ee2ca8f..d3a93debd1 100644
--- a/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/Smtp/EsmtpTransport.php
@@ -29,8 +29,8 @@ use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
 class EsmtpTransport extends SmtpTransport
 {
     private $authenticators = [];
-    private $username;
-    private $password;
+    private $username = '';
+    private $password = '';
     private $authMode;
 
     public function __construct(string $host = 'localhost', int $port = 25, string $encryption = null, string $authMode = null, EventDispatcherInterface $dispatcher = null, LoggerInterface $logger = null)