diff --git a/application/Espo/Core/Mail/Sender.php b/application/Espo/Core/Mail/Sender.php
index 1c7050b4ab..da6deacef1 100644
--- a/application/Espo/Core/Mail/Sender.php
+++ b/application/Espo/Core/Mail/Sender.php
@@ -32,7 +32,6 @@ namespace Espo\Core\Mail;
 use Espo\Core\FileStorage\Manager as FileStorageManager;
 use Espo\Core\Mail\Exceptions\NoSmtp;
 use Espo\Core\Mail\Sender\DefaultTransportPreparator;
-use Espo\Core\Mail\Sender\TransportPreparator;
 use Espo\Core\ORM\Repository\Option\SaveOption;
 use Espo\ORM\EntityCollection;
 use Espo\Core\Field\DateTime;
diff --git a/application/Espo/Core/Mail/SmtpParams.php b/application/Espo/Core/Mail/SmtpParams.php
index ef36c2bf26..217507a827 100644
--- a/application/Espo/Core/Mail/SmtpParams.php
+++ b/application/Espo/Core/Mail/SmtpParams.php
@@ -44,8 +44,6 @@ class SmtpParams
     private ?array $connectionOptions = null;
     private bool $auth = false;
     private ?string $authMechanism = null;
-    /** @var ?class-string */
-    private ?string $authClassName = null;
     private ?string $username = null;
     private ?string $password = null;
     private ?string $security = null;
@@ -64,7 +62,6 @@ class SmtpParams
         'connectionOptions',
         'auth',
         'authMechanism',
-        'authClassName',
         'username',
         'password',
         'security',
@@ -127,11 +124,6 @@ class SmtpParams
             }
         }
 
-        if (isset($params['smtpAuthClassName'])) {
-            // For bc.
-            $obj->authClassName = $params['smtpAuthClassName'];
-        }
-
         return $obj;
     }
 
@@ -173,14 +165,6 @@ class SmtpParams
         return $this->authMechanism;
     }
 
-    /**
-     * @return ?class-string
-     */
-    public function getAuthClassName(): ?string
-    {
-        return $this->authClassName;
-    }
-
     public function getUsername(): ?string
     {
         return $this->username;
@@ -239,17 +223,6 @@ class SmtpParams
         return $obj;
     }
 
-    /**
-     * @param ?class-string $authClassName
-     */
-    public function withAuthClassName(?string $authClassName): self
-    {
-        $obj = clone $this;
-        $obj->authClassName = $authClassName;
-
-        return $obj;
-    }
-
     public function withUsername(?string $username): self
     {
         $obj = clone $this;
diff --git a/tests/unit/Espo/Core/Mail/SmtpParamsTest.php b/tests/unit/Espo/Core/Mail/SmtpParamsTest.php
index 3966d06bf4..c272b0d000 100644
--- a/tests/unit/Espo/Core/Mail/SmtpParamsTest.php
+++ b/tests/unit/Espo/Core/Mail/SmtpParamsTest.php
@@ -30,8 +30,9 @@
 namespace tests\unit\Espo\Core\Mail;
 
 use Espo\Core\Mail\SmtpParams;
+use PHPUnit\Framework\TestCase;
 
-class SmtpParamsTest extends \PHPUnit\Framework\TestCase
+class SmtpParamsTest extends TestCase
 {
     public function testFromArray1(): void
     {
@@ -56,7 +57,6 @@ class SmtpParamsTest extends \PHPUnit\Framework\TestCase
             'auth' => true,
             'connectionOptions' => ['test' => 'test'],
             'authMechanism' => 'login',
-            'authClassName' => 'Test',
             'username' => 'tester',
             'password' => 'password',
             'security' => 'ssl',
@@ -74,7 +74,6 @@ class SmtpParamsTest extends \PHPUnit\Framework\TestCase
             ->withUsername('tester')
             ->withPassword('test')
             ->withAuthMechanism('login')
-            ->withAuthClassName('Test')
             ->withConnectionOptions(['test' => 'test']);
 
         $this->assertEquals('localhost', $params->getServer());
@@ -88,6 +87,5 @@ class SmtpParamsTest extends \PHPUnit\Framework\TestCase
         $this->assertEquals('tester', $params->getUsername());
         $this->assertEquals('test', $params->getPassword());
         $this->assertEquals(['test' => 'test'], $params->getConnectionOptions());
-        $this->assertEquals('Test', $params->getAuthClassName());
     }
 }