diff --git a/src/Symfony/Component/Mailer/Mailer.php b/src/Symfony/Component/Mailer/Mailer.php
index 8aa357de4c..44740ba23a 100644
--- a/src/Symfony/Component/Mailer/Mailer.php
+++ b/src/Symfony/Component/Mailer/Mailer.php
@@ -12,7 +12,6 @@
 namespace Symfony\Component\Mailer;
 
 use Symfony\Component\Mailer\Event\MessageEvent;
-use Symfony\Component\Mailer\Exception\TransportException;
 use Symfony\Component\Mailer\Messenger\SendEmailMessage;
 use Symfony\Component\Mailer\Transport\TransportInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
@@ -45,15 +44,7 @@ final class Mailer implements MailerInterface
 
         if (null !== $this->dispatcher) {
             $message = clone $message;
-            if (null !== $envelope) {
-                $envelope = clone $envelope;
-            } else {
-                try {
-                    $envelope = new DelayedSmtpEnvelope($message);
-                } catch (\Exception $e) {
-                    throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
-                }
-            }
+            $envelope = null !== $envelope ? clone $envelope : SmtpEnvelope::create($message);
             $event = new MessageEvent($message, $envelope, (string) $this->transport, true);
             $this->dispatcher->dispatch($event);
         }
diff --git a/src/Symfony/Component/Mailer/SmtpEnvelope.php b/src/Symfony/Component/Mailer/SmtpEnvelope.php
index e9fb7bf4e7..edf6992118 100644
--- a/src/Symfony/Component/Mailer/SmtpEnvelope.php
+++ b/src/Symfony/Component/Mailer/SmtpEnvelope.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Mailer;
 
 use Symfony\Component\Mailer\Exception\InvalidArgumentException;
+use Symfony\Component\Mailer\Exception\LogicException;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\RawMessage;
 
@@ -34,6 +35,10 @@ class SmtpEnvelope
 
     public static function create(RawMessage $message): self
     {
+        if (RawMessage::class === \get_class($message)) {
+            throw new LogicException('Cannot send a RawMessage instance without an explicit Envelope.');
+        }
+
         return new DelayedSmtpEnvelope($message);
     }
 
diff --git a/src/Symfony/Component/Mailer/Tests/MailerTest.php b/src/Symfony/Component/Mailer/Tests/MailerTest.php
new file mode 100644
index 0000000000..dd9d5a95ad
--- /dev/null
+++ b/src/Symfony/Component/Mailer/Tests/MailerTest.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Mailer\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Exception\LogicException;
+use Symfony\Component\Mailer\Mailer;
+use Symfony\Component\Mailer\Transport\TransportInterface;
+use Symfony\Component\Messenger\MessageBusInterface;
+use Symfony\Component\Mime\RawMessage;
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
+
+class MailerTest extends TestCase
+{
+    public function testSendingRawMessages()
+    {
+        $this->expectException(LogicException::class);
+
+        $transport = new Mailer($this->createMock(TransportInterface::class), $this->createMock(MessageBusInterface::class), $this->createMock(EventDispatcherInterface::class));
+        $transport->send(new RawMessage('Some raw email message'));
+    }
+}
diff --git a/src/Symfony/Component/Mailer/Tests/SmtpEnvelopeTest.php b/src/Symfony/Component/Mailer/Tests/SmtpEnvelopeTest.php
index 6905b2cebd..85f4e11306 100644
--- a/src/Symfony/Component/Mailer/Tests/SmtpEnvelopeTest.php
+++ b/src/Symfony/Component/Mailer/Tests/SmtpEnvelopeTest.php
@@ -12,10 +12,12 @@
 namespace Symfony\Component\Mailer\Tests;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Exception\LogicException;
 use Symfony\Component\Mailer\SmtpEnvelope;
 use Symfony\Component\Mime\Address;
 use Symfony\Component\Mime\Header\Headers;
 use Symfony\Component\Mime\Message;
+use Symfony\Component\Mime\RawMessage;
 
 class SmtpEnvelopeTest extends TestCase
 {
@@ -89,4 +91,11 @@ class SmtpEnvelopeTest extends TestCase
         $e = SmtpEnvelope::create(new Message($headers));
         $this->assertEquals([new Address('to@symfony.com'), new Address('cc@symfony.com'), new Address('bcc@symfony.com')], $e->getRecipients());
     }
+
+    public function testFromRawMessages()
+    {
+        $this->expectException(LogicException::class);
+
+        SmtpEnvelope::create(new RawMessage('Some raw email message'));
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
index 1d0bee96f6..192f5edf40 100644
--- a/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
+++ b/src/Symfony/Component/Mailer/Tests/Transport/AbstractTransportTest.php
@@ -12,6 +12,7 @@
 namespace Symfony\Component\Mailer\Tests\Transport;
 
 use PHPUnit\Framework\TestCase;
+use Symfony\Component\Mailer\Exception\LogicException;
 use Symfony\Component\Mailer\SmtpEnvelope;
 use Symfony\Component\Mailer\Transport\NullTransport;
 use Symfony\Component\Mime\Address;
@@ -46,4 +47,12 @@ class AbstractTransportTest extends TestCase
         $transport->send($message, $envelope);
         $this->assertEqualsWithDelta(0, time() - $start, 1);
     }
+
+    public function testSendingRawMessages()
+    {
+        $this->expectException(LogicException::class);
+
+        $transport = new NullTransport();
+        $transport->send(new RawMessage('Some raw email message'));
+    }
 }
diff --git a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
index fb817f75b5..b7cabb04ad 100644
--- a/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
+++ b/src/Symfony/Component/Mailer/Transport/AbstractTransport.php
@@ -13,9 +13,7 @@ namespace Symfony\Component\Mailer\Transport;
 
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
-use Symfony\Component\Mailer\DelayedSmtpEnvelope;
 use Symfony\Component\Mailer\Event\MessageEvent;
-use Symfony\Component\Mailer\Exception\TransportException;
 use Symfony\Component\Mailer\SentMessage;
 use Symfony\Component\Mailer\SmtpEnvelope;
 use Symfony\Component\Mime\Address;
@@ -56,15 +54,7 @@ abstract class AbstractTransport implements TransportInterface
     public function send(RawMessage $message, SmtpEnvelope $envelope = null): ?SentMessage
     {
         $message = clone $message;
-        if (null !== $envelope) {
-            $envelope = clone $envelope;
-        } else {
-            try {
-                $envelope = new DelayedSmtpEnvelope($message);
-            } catch (\Exception $e) {
-                throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
-            }
-        }
+        $envelope = null !== $envelope ? clone $envelope : SmtpEnvelope::create($message);
 
         if (null !== $this->dispatcher) {
             $event = new MessageEvent($message, $envelope, (string) $this);