diff --git a/app/Notifications/Channels/EmailChannel.php b/app/Notifications/Channels/EmailChannel.php
index 429b5a0bb..e255f5aa5 100644
--- a/app/Notifications/Channels/EmailChannel.php
+++ b/app/Notifications/Channels/EmailChannel.php
@@ -4,13 +4,13 @@
 
 use App\Exceptions\NonReportableException;
 use App\Models\Team;
+use App\Support\SmtpTransportFactory;
 use Exception;
 use Illuminate\Notifications\Notification;
 use Resend;
 use Resend\Exceptions\ErrorException;
 use Resend\Exceptions\TransporterException;
 use Symfony\Component\Mailer\Mailer;
-use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;
 use Symfony\Component\Mime\Email;
 
 class EmailChannel
@@ -82,21 +82,7 @@ public function send(SendsEmail $notifiable, Notification $notification): void
                     'html' => (string) $mailMessage->render(),
                 ]);
             } elseif ($isSmtpEnabled) {
-                $encryption = match (strtolower($settings->smtp_encryption)) {
-                    'starttls' => null,
-                    'tls' => 'tls',
-                    'none' => null,
-                    default => null,
-                };
-
-                $transport = new EsmtpTransport(
-                    $settings->smtp_host,
-                    $settings->smtp_port,
-                    $encryption
-                );
-                $transport->setUsername($settings->smtp_username ?? '');
-                $transport->setPassword($settings->smtp_password ?? '');
-
+                $transport = SmtpTransportFactory::fromSettings($settings);
                 $mailer = new Mailer($transport);
 
                 $email = (new Email)
diff --git a/app/Services/ConfigurationRepository.php b/app/Services/ConfigurationRepository.php
index 34d8a231f..422612e1e 100644
--- a/app/Services/ConfigurationRepository.php
+++ b/app/Services/ConfigurationRepository.php
@@ -2,6 +2,7 @@
 
 namespace App\Services;
 
+use App\Support\SmtpTransportFactory;
 use Illuminate\Config\Repository;
 use Illuminate\Support\Facades\Mail;
 
@@ -27,25 +28,21 @@ public function updateMailConfig($settings): void
         }
 
         if ($settings->smtp_enabled) {
-            $encryption = match (strtolower($settings->smtp_encryption)) {
-                'starttls' => null,
-                'tls' => 'tls',
-                'none' => null,
-                default => null,
-            };
+            $mailerOptions = SmtpTransportFactory::mailerOptions($settings);
 
             $this->config->set('mail.default', 'smtp');
             $this->applyMailFrom($from);
             $this->config->set('mail.mailers.smtp', [
                 'transport' => 'smtp',
+                'scheme' => $mailerOptions['scheme'],
                 'host' => $settings->smtp_host,
                 'port' => $settings->smtp_port,
-                'encryption' => $encryption,
+                'encryption' => $mailerOptions['encryption'],
                 'username' => $settings->smtp_username,
                 'password' => $settings->smtp_password,
                 'timeout' => $settings->smtp_timeout,
                 'local_domain' => null,
-                'auto_tls' => $settings->smtp_encryption === 'none' ? '0' : '',
+                'auto_tls' => $mailerOptions['auto_tls'],
             ]);
         }
     }
diff --git a/app/Support/SmtpTransportFactory.php b/app/Support/SmtpTransportFactory.php
new file mode 100644
index 000000000..1b4d4b09a
--- /dev/null
+++ b/app/Support/SmtpTransportFactory.php
@@ -0,0 +1,63 @@
+<?php
+
+namespace App\Support;
+
+use Symfony\Component\Mailer\Transport\Smtp\EsmtpTransport;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
+
+class SmtpTransportFactory
+{
+    public static function fromSettings(object $settings): EsmtpTransport
+    {
+        $mode = self::encryptionMode($settings);
+
+        $transport = new EsmtpTransport(
+            $settings->smtp_host,
+            (int) $settings->smtp_port,
+            match ($mode) {
+                'none' => false,
+                'tls' => true,
+                default => null,
+            }
+        );
+
+        if ($mode === 'none') {
+            $transport->setAutoTls(false);
+        }
+
+        $transport->setUsername($settings->smtp_username ?? '');
+        $transport->setPassword($settings->smtp_password ?? '');
+
+        $stream = $transport->getStream();
+        if (isset($settings->smtp_timeout) && $stream instanceof SocketStream) {
+            $stream->setTimeout((float) $settings->smtp_timeout);
+        }
+
+        return $transport;
+    }
+
+    /**
+     * @return array{scheme: ?string, encryption: ?string, auto_tls: string}
+     */
+    public static function mailerOptions(object $settings): array
+    {
+        $mode = self::encryptionMode($settings);
+
+        return [
+            'scheme' => match ($mode) {
+                'none', 'starttls' => 'smtp',
+                'tls' => 'smtps',
+                default => null,
+            },
+            'encryption' => $mode === 'tls' ? 'tls' : null,
+            'auto_tls' => $mode === 'none' ? '0' : '',
+        ];
+    }
+
+    private static function encryptionMode(object $settings): ?string
+    {
+        return $settings->smtp_encryption === null
+            ? null
+            : strtolower((string) $settings->smtp_encryption);
+    }
+}
diff --git a/tests/Unit/ConfigurationRepositoryMailConfigTest.php b/tests/Unit/ConfigurationRepositoryMailConfigTest.php
new file mode 100644
index 000000000..e5592b5e4
--- /dev/null
+++ b/tests/Unit/ConfigurationRepositoryMailConfigTest.php
@@ -0,0 +1,29 @@
+<?php
+
+use App\Services\ConfigurationRepository;
+use Illuminate\Config\Repository;
+
+it('configures the laravel smtp scheme from encryption', function (string $mode, int $port, string $scheme, ?string $encryption, string $autoTls) {
+    $config = new Repository;
+    $repository = new ConfigurationRepository($config);
+
+    $repository->updateMailConfig((object) [
+        'resend_enabled' => false,
+        'smtp_enabled' => true,
+        'smtp_encryption' => $mode,
+        'smtp_host' => 'smtp.example.com',
+        'smtp_port' => $port,
+        'smtp_username' => 'user',
+        'smtp_password' => 'secret',
+        'smtp_timeout' => null,
+        'smtp_from_address' => 'from@example.com',
+        'smtp_from_name' => 'Coolify',
+    ]);
+
+    expect($config->get('mail.mailers.smtp.scheme'))->toBe($scheme)
+        ->and($config->get('mail.mailers.smtp.encryption'))->toBe($encryption)
+        ->and($config->get('mail.mailers.smtp.auto_tls'))->toBe($autoTls);
+})->with([
+    'none on port 465' => ['none', 465, 'smtp', null, '0'],
+    'tls on a non-465 port' => ['tls', 587, 'smtps', 'tls', ''],
+]);
diff --git a/tests/Unit/SmtpTransportFactoryTest.php b/tests/Unit/SmtpTransportFactoryTest.php
new file mode 100644
index 000000000..168547661
--- /dev/null
+++ b/tests/Unit/SmtpTransportFactoryTest.php
@@ -0,0 +1,112 @@
+<?php
+
+use App\Support\SmtpTransportFactory;
+use Symfony\Component\Mailer\Transport\Smtp\Stream\SocketStream;
+
+function smtpSettings(array $overrides = []): object
+{
+    return (object) array_merge([
+        'smtp_host' => 'smtp.example.com',
+        'smtp_port' => 25,
+        'smtp_encryption' => 'none',
+        'smtp_username' => 'user',
+        'smtp_password' => 'secret',
+        'smtp_timeout' => null,
+    ], $overrides);
+}
+
+it('disables opportunistic STARTTLS when encryption is none', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => 'none',
+    ]));
+
+    expect($transport->isAutoTls())->toBeFalse()
+        ->and($transport->getStream())->toBeInstanceOf(SocketStream::class)
+        ->and($transport->getStream()->isTLS())->toBeFalse();
+});
+
+it('does not issue STARTTLS for the issue 5877 anonymous port 25 relay', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => 'none',
+        'smtp_port' => 25,
+        'smtp_username' => '',
+        'smtp_password' => '',
+    ]));
+
+    expect($transport->isAutoTls())->toBeFalse()
+        ->and($transport->getStream()->isTLS())->toBeFalse()
+        ->and($transport->getStream()->getPort())->toBe(25)
+        ->and($transport->getUsername())->toBe('')
+        ->and($transport->getPassword())->toBe('');
+});
+
+it('does not enable implicit TLS on port 465 when encryption is none', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => 'none',
+        'smtp_port' => 465,
+    ]));
+
+    expect($transport->isAutoTls())->toBeFalse()
+        ->and($transport->getStream()->isTLS())->toBeFalse();
+});
+
+it('keeps opportunistic STARTTLS when encryption is starttls', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => 'starttls',
+    ]));
+
+    expect($transport->isAutoTls())->toBeTrue()
+        ->and($transport->getStream()->isTLS())->toBeFalse();
+});
+
+it('uses implicit TLS when encryption is tls', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => 'tls',
+        'smtp_port' => 465,
+    ]));
+
+    expect($transport->isAutoTls())->toBeTrue()
+        ->and($transport->getStream()->isTLS())->toBeTrue();
+});
+
+it('infers implicit TLS on port 465 when encryption is null', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_encryption' => null,
+        'smtp_port' => 465,
+    ]));
+
+    expect($transport->getStream()->isTLS())->toBeTrue();
+});
+
+it('applies a configured SMTP timeout to the transport stream', function () {
+    $transport = SmtpTransportFactory::fromSettings(smtpSettings([
+        'smtp_timeout' => 15,
+    ]));
+
+    expect($transport->getStream()->getTimeout())->toBe(15.0);
+});
+
+it('maps none encryption to laravel mailer options that disable auto tls', function () {
+    expect(SmtpTransportFactory::mailerOptions(smtpSettings([
+        'smtp_encryption' => 'none',
+    ])))->toBe([
+        'scheme' => 'smtp',
+        'encryption' => null,
+        'auto_tls' => '0',
+    ]);
+});
+
+it('maps encryption to laravel mailer options', function (?string $mode, ?string $scheme, ?string $encryption) {
+    expect(SmtpTransportFactory::mailerOptions(smtpSettings([
+        'smtp_encryption' => $mode,
+    ])))->toBe([
+        'scheme' => $scheme,
+        'encryption' => $encryption,
+        'auto_tls' => $mode === 'none' ? '0' : '',
+    ]);
+})->with([
+    'none' => ['none', 'smtp', null],
+    'starttls' => ['starttls', 'smtp', null],
+    'tls' => ['tls', 'smtps', 'tls'],
+    'unset' => [null, null, null],
+]);