diff --git a/src/Controller/Admin/AdministratorController.php b/src/Controller/Admin/AdministratorController.php
index 87400124b6..8bcfb84eed 100644
--- a/src/Controller/Admin/AdministratorController.php
+++ b/src/Controller/Admin/AdministratorController.php
@@ -18,7 +18,6 @@
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\AdministratorNotFoundException;
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\DeletingLastAdministratorException;
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\DeletingSelfException;
-use Shopsys\FrameworkBundle\Model\Administrator\Exception\DuplicateUserNameException;
 use Shopsys\FrameworkBundle\Model\Administrator\Security\AdministratorRolesChangedFacade;
 use Shopsys\FrameworkBundle\Model\AdminNavigation\BreadcrumbOverrider;
 use Shopsys\FrameworkBundle\Model\Security\Authenticator;
@@ -121,30 +120,23 @@ public function editAction(Request $request, int $id)
         $form->handleRequest($request);
 
         if ($form->isSubmitted() && $form->isValid()) {
-            try {
-                $this->administratorFacade->edit($id, $administratorData);
-
-                if ($loggedUser->getId() === $id) {
-                    $this->administratorRolesChangedFacade->refreshAdministratorToken($administrator);
-                }
-
-                $this->addSuccessFlashTwig(
-                    t('Administrator <strong><a href="{{ url }}">{{ name }}</a></strong> modified'),
-                    [
-                        'name' => $administratorData->realName,
-                        'url' => $this->generateUrl('admin_administrator_edit', ['id' => $administrator->getId()]),
-                    ],
-                );
-
-                return $this->redirectToRoute('admin_administrator_list');
-            } catch (DuplicateUserNameException $ex) {
-                $this->addErrorFlashTwig(
-                    t('Login name <strong>{{ name }}</strong> is already used'),
-                    [
-                        'name' => $administratorData->username,
-                    ],
-                );
+            $this->administratorFacade->edit($id, $administratorData);
+
+            if ($loggedUser->getId() === $id) {
+                $this->administratorRolesChangedFacade->refreshAdministratorToken($administrator);
             }
+
+            $this->addSuccessFlashTwig(
+                t('Administrator <strong><a href="{{ url }}">{{ name }}</a></strong> modified'),
+                [
+                    'name' => $administratorData->realName,
+                    'url' => $this->generateUrl('admin_administrator_edit', ['id' => $administrator->getId()]),
+                ],
+            );
+
+            $redirectRouteName = $this->isGranted(Roles::ROLE_ADMINISTRATOR_VIEW) ? 'admin_administrator_list' : 'admin_default_dashboard';
+
+            return $this->redirectToRoute($redirectRouteName);
         }
 
         if ($form->isSubmitted() && !$form->isValid()) {
@@ -193,27 +185,18 @@ public function newAction(Request $request)
         if ($form->isSubmitted() && $form->isValid()) {
             $administratorData = $form->getData();
 
-            try {
-                $administrator = $this->administratorFacade->create($administratorData);
-                $this->administratorPasswordFacade->resetPassword($administrator->getUsername());
-
-                $this->addSuccessFlashTwig(
-                    t('Administrator <strong><a href="{{ url }}">{{ name }}</a></strong> created. A link to set a password has been sent to his email.'),
-                    [
-                        'name' => $administrator->getRealName(),
-                        'url' => $this->generateUrl('admin_administrator_edit', ['id' => $administrator->getId()]),
-                    ],
-                );
-
-                return $this->redirectToRoute('admin_administrator_list');
-            } catch (DuplicateUserNameException $ex) {
-                $this->addErrorFlashTwig(
-                    t('Login name <strong>{{ name }}</strong> is already used'),
-                    [
-                        'name' => $administratorData->username,
-                    ],
-                );
-            }
+            $administrator = $this->administratorFacade->create($administratorData);
+            $this->administratorPasswordFacade->resetPassword($administrator->getUsername());
+
+            $this->addSuccessFlashTwig(
+                t('Administrator <strong><a href="{{ url }}">{{ name }}</a></strong> created. A link to set a password has been sent to his email.'),
+                [
+                    'name' => $administrator->getRealName(),
+                    'url' => $this->generateUrl('admin_administrator_edit', ['id' => $administrator->getId()]),
+                ],
+            );
+
+            return $this->redirectToRoute('admin_administrator_list');
         }
 
         if ($form->isSubmitted() && !$form->isValid()) {
@@ -551,7 +534,9 @@ public function setNewPasswordAction(Request $request): Response
                 $this->authenticator->loginAdministrator($administrator);
             }
 
-            return $this->redirectToRoute('admin_administrator_list');
+            $this->addSuccessFlash(t('Password has been successfully set.'));
+
+            return $this->redirectToRoute('admin_default_dashboard');
         }
 
         if ($form->isSubmitted() && !$form->isValid()) {
diff --git a/src/Form/Admin/Administrator/AdministratorFormType.php b/src/Form/Admin/Administrator/AdministratorFormType.php
index 43b7ddedb8..6f0c350ecf 100644
--- a/src/Form/Admin/Administrator/AdministratorFormType.php
+++ b/src/Form/Admin/Administrator/AdministratorFormType.php
@@ -6,6 +6,7 @@
 
 use Shopsys\FrameworkBundle\Component\Router\Security\RouteCsrfProtector;
 use Shopsys\FrameworkBundle\Form\Constraints\Email;
+use Shopsys\FrameworkBundle\Form\Constraints\UniqueEntityField;
 use Shopsys\FrameworkBundle\Form\DisplayOnlyType;
 use Shopsys\FrameworkBundle\Form\DisplayOnlyUrlType;
 use Shopsys\FrameworkBundle\Form\GroupType;
@@ -68,6 +69,12 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
                     new Constraints\Length(
                         ['max' => 100, 'maxMessage' => 'Username cannot be longer than {{ limit }} characters'],
                     ),
+                    new UniqueEntityField([
+                        'entityInstance' => $options['administrator'],
+                        'message' => 'Administrator with user name "{{ value }}" is already registered',
+                        'fieldName' => 'username',
+                        'entityName' => Administrator::class,
+                    ]),
                 ],
                 'label' => t('Login name'),
             ])
@@ -88,6 +95,12 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
                     new Constraints\Length(
                         ['max' => 255, 'maxMessage' => 'Email cannot be longer than {{ limit }} characters'],
                     ),
+                    new UniqueEntityField([
+                        'entityInstance' => $options['administrator'],
+                        'message' => 'Administrator with email "{{ value }}" is already registered',
+                        'fieldName' => 'email',
+                        'entityName' => Administrator::class,
+                    ]),
                 ],
                 'label' => t('Email'),
             ]);
diff --git a/src/Form/Constraints/UniqueEntityField.php b/src/Form/Constraints/UniqueEntityField.php
new file mode 100644
index 0000000000..86ccfb094b
--- /dev/null
+++ b/src/Form/Constraints/UniqueEntityField.php
@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopsys\FrameworkBundle\Form\Constraints;
+
+use Symfony\Component\Validator\Constraint;
+
+class UniqueEntityField extends Constraint
+{
+    public string $message = 'The "{{ value }}" value of "{{ fieldName }}" field must be unique';
+
+    public string $fieldName;
+
+    public string $entityName;
+
+    public ?object $entityInstance = null;
+}
diff --git a/src/Form/Constraints/UniqueEntityFieldValidator.php b/src/Form/Constraints/UniqueEntityFieldValidator.php
new file mode 100644
index 0000000000..71b4bba2e5
--- /dev/null
+++ b/src/Form/Constraints/UniqueEntityFieldValidator.php
@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopsys\FrameworkBundle\Form\Constraints;
+
+use Doctrine\ORM\EntityManagerInterface;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+class UniqueEntityFieldValidator extends ConstraintValidator
+{
+    /**
+     * @param \Doctrine\ORM\EntityManagerInterface $em
+     */
+    public function __construct(
+        protected readonly EntityManagerInterface $em,
+    ) {
+    }
+
+    /**
+     * @param mixed $value
+     * @param \Symfony\Component\Validator\Constraint $constraint
+     */
+    public function validate(mixed $value, Constraint $constraint): void
+    {
+        if (!$constraint instanceof UniqueEntityField) {
+            throw new UnexpectedTypeException($constraint, UniqueEntityField::class);
+        }
+
+        if ($value === null || $value === '') {
+            return;
+        }
+
+        $entity = $this->em->getRepository($constraint->entityName)->findOneBy([$constraint->fieldName => $value]);
+
+        if ($entity !== null && $entity !== $constraint->entityInstance) {
+            $this->context->buildViolation($constraint->message)
+                ->setParameter('{{ value }}', $value)
+                ->setParameter('{{ fieldName }}', $constraint->fieldName)
+                ->addViolation();
+        }
+    }
+}
diff --git a/src/Migrations/Version20180702111015.php b/src/Migrations/Version20180702111015.php
index 5da823acec..f828f7b57a 100644
--- a/src/Migrations/Version20180702111015.php
+++ b/src/Migrations/Version20180702111015.php
@@ -25,7 +25,7 @@ public function up(Schema $schema): void
 
         $this->sql(
             'INSERT INTO administrators (id, username, real_name, password, login_token, email, superadmin) VALUES '
-            . '(1, \'superadmin\', \'superadmin\', \'$2y$12$ppwYj/By0pDkiLlE.ssf6uuwCvtfdDfsJJNr84fU59HmxSfj0luSC\', \'\', \'no-reply@shopsys.com\', true),'
+            . '(1, \'superadmin\', \'superadmin\', \'$2y$12$ppwYj/By0pDkiLlE.ssf6uuwCvtfdDfsJJNr84fU59HmxSfj0luSC\', \'\', \'no-reply.1@shopsys.com\', true),'
             . '(2, \'admin\', \'admin\', \'$2y$12$tRU86hi0UxWEMQzP08nl..hKiClF.Pj3D1oIcKDL.aA7ph2Vomwh2\', \'\', \'no-reply@shopsys.com\', false)',
         );
 
diff --git a/src/Migrations/Version20241220094923.php b/src/Migrations/Version20241220094923.php
new file mode 100644
index 0000000000..74951eb712
--- /dev/null
+++ b/src/Migrations/Version20241220094923.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shopsys\FrameworkBundle\Migrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Shopsys\MigrationBundle\Component\Doctrine\Migrations\AbstractMigration;
+
+class Version20241220094923 extends AbstractMigration
+{
+    /**
+     * @param \Doctrine\DBAL\Schema\Schema $schema
+     */
+    public function up(Schema $schema): void
+    {
+        $this->sql('CREATE UNIQUE INDEX UNIQ_73A716FE7927C74 ON administrators (email)');
+    }
+
+    /**
+     * @param \Doctrine\DBAL\Schema\Schema $schema
+     */
+    public function down(Schema $schema): void
+    {
+    }
+}
diff --git a/src/Model/Administrator/Administrator.php b/src/Model/Administrator/Administrator.php
index 723ce994c0..97e885208c 100644
--- a/src/Model/Administrator/Administrator.php
+++ b/src/Model/Administrator/Administrator.php
@@ -80,7 +80,7 @@ class Administrator implements UserInterface, UniqueLoginInterface, TimelimitLog
 
     /**
      * @var string
-     * @ORM\Column(type="string", length=255)
+     * @ORM\Column(type="string", length=255, unique=true)
      */
     protected $email;
 
diff --git a/src/Model/Administrator/AdministratorFacade.php b/src/Model/Administrator/AdministratorFacade.php
index 454396cf26..ce54c2f4b6 100644
--- a/src/Model/Administrator/AdministratorFacade.php
+++ b/src/Model/Administrator/AdministratorFacade.php
@@ -10,7 +10,6 @@
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\DeletingLastAdministratorException;
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\DeletingSelfException;
 use Shopsys\FrameworkBundle\Model\Administrator\Exception\DeletingSuperadminException;
-use Shopsys\FrameworkBundle\Model\Administrator\Exception\DuplicateUserNameException;
 use Shopsys\FrameworkBundle\Model\Administrator\Role\AdministratorRoleFacade;
 use Shopsys\FrameworkBundle\Model\Administrator\Security\Exception\AdministratorIsNotLoggedException;
 use Symfony\Component\PasswordHasher\Hasher\PasswordHasherFactoryInterface;
@@ -42,11 +41,6 @@ public function __construct(
      */
     public function create(AdministratorData $administratorData): Administrator
     {
-        $administratorByUserName = $this->administratorRepository->findByUserName($administratorData->username);
-
-        if ($administratorByUserName !== null) {
-            throw new DuplicateUserNameException($administratorByUserName->getUsername());
-        }
         $administrator = $this->administratorFactory->create($administratorData);
 
         $this->em->persist($administrator);
@@ -65,7 +59,6 @@ public function create(AdministratorData $administratorData): Administrator
     public function edit($administratorId, AdministratorData $administratorData): Administrator
     {
         $administrator = $this->administratorRepository->getById($administratorId);
-        $this->checkUsername($administrator, $administratorData->username);
         $administrator->edit($administratorData);
 
         $this->em->flush();
@@ -75,22 +68,6 @@ public function edit($administratorId, AdministratorData $administratorData): Ad
         return $administrator;
     }
 
-    /**
-     * @param \Shopsys\FrameworkBundle\Model\Administrator\Administrator $administrator
-     * @param string $username
-     */
-    protected function checkUsername(Administrator $administrator, string $username): void
-    {
-        $administratorByUserName = $this->administratorRepository->findByUserName($username);
-
-        if ($administratorByUserName !== null
-            && $administratorByUserName !== $administrator
-            && $administratorByUserName->getUsername() === $username
-        ) {
-            throw new DuplicateUserNameException($administrator->getUsername());
-        }
-    }
-
     /**
      * @param int $administratorId
      */
diff --git a/src/Model/Administrator/Exception/DuplicateUserNameException.php b/src/Model/Administrator/Exception/DuplicateUserNameException.php
deleted file mode 100644
index 4bddc183d3..0000000000
--- a/src/Model/Administrator/Exception/DuplicateUserNameException.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace Shopsys\FrameworkBundle\Model\Administrator\Exception;
-
-use Exception;
-
-class DuplicateUserNameException extends Exception implements AdministratorException
-{
-    /**
-     * @param string $username
-     * @param \Exception|null $previous
-     */
-    public function __construct($username, ?Exception $previous = null)
-    {
-        parent::__construct('Administrator with user name ' . $username . ' already exists.', 0, $previous);
-    }
-}
diff --git a/src/Resources/translations/messages.cs.po b/src/Resources/translations/messages.cs.po
index cbf738e004..dfe2142059 100644
--- a/src/Resources/translations/messages.cs.po
+++ b/src/Resources/translations/messages.cs.po
@@ -2356,9 +2356,6 @@ msgstr "Přihlášení se nepodařilo."
 msgid "Login name"
 msgstr "Přihlašovací jméno"
 
-msgid "Login name <strong>{{ name }}</strong> is already used"
-msgstr "Přihlašovací jméno <strong>{{ name }}</strong> je již použito"
-
 msgid "Login time"
 msgstr "Čas přihlášení"
 
@@ -3013,6 +3010,9 @@ msgstr "Heslo"
 msgid "Password again"
 msgstr "Heslo znovu"
 
+msgid "Password has been successfully set."
+msgstr "Heslo bylo úspěšně nastaveno."
+
 msgid "Password has to include uppercase letters, lowercase letters, numbers and must be longer than 10 characters."
 msgstr "Heslo musí obsahovat velká písmena, malá písmena, číslice a musí být delší než 10 znaků."
 
diff --git a/src/Resources/translations/messages.en.po b/src/Resources/translations/messages.en.po
index 8a50dcb2f5..e29a260eec 100644
--- a/src/Resources/translations/messages.en.po
+++ b/src/Resources/translations/messages.en.po
@@ -2356,9 +2356,6 @@ msgstr ""
 msgid "Login name"
 msgstr ""
 
-msgid "Login name <strong>{{ name }}</strong> is already used"
-msgstr ""
-
 msgid "Login time"
 msgstr ""
 
@@ -3013,6 +3010,9 @@ msgstr ""
 msgid "Password again"
 msgstr ""
 
+msgid "Password has been successfully set."
+msgstr ""
+
 msgid "Password has to include uppercase letters, lowercase letters, numbers and must be longer than 10 characters."
 msgstr ""
 
diff --git a/src/Resources/translations/validators.cs.po b/src/Resources/translations/validators.cs.po
index 7392740973..e839c485ff 100644
--- a/src/Resources/translations/validators.cs.po
+++ b/src/Resources/translations/validators.cs.po
@@ -7,6 +7,12 @@ msgstr ""
 msgid "Address {{ url }} already exists."
 msgstr "Adresa {{ url }} již existuje."
 
+msgid "Administrator with email \"{{ value }}\" is already registered"
+msgstr "Aministrátor s e-mailem \"{{ value }}\" je již registrován"
+
+msgid "Administrator with user name \"{{ value }}\" is already registered"
+msgstr "Aministrátor s uživatelským jménem \"{{ value }}\" je již registrován"
+
 msgid "Amount of money should be greater than or equal to zero."
 msgstr "Tato částka musí být větší nebo rovna nule."
 
@@ -547,6 +553,9 @@ msgstr "DIČ nesmí být delší než {{ limit }} znaků"
 msgid "Telephone number cannot be longer than {{ limit }} characters"
 msgstr "Telefon nesmí být delší než {{ limit }} znaků"
 
+msgid "The \"{{ value }}\" value of \"{{ fieldName }}\" field must be unique"
+msgstr "Hodnota \"{{ value }}\" pole \"{{ fieldName }}\" musí být unikátní"
+
 msgid "The amount of money should be {{ limit }} or less."
 msgstr "Tato částka musí být {{ limit }} nebo méně."
 
diff --git a/src/Resources/translations/validators.en.po b/src/Resources/translations/validators.en.po
index 627a23a084..3c0138118f 100644
--- a/src/Resources/translations/validators.en.po
+++ b/src/Resources/translations/validators.en.po
@@ -7,6 +7,12 @@ msgstr ""
 msgid "Address {{ url }} already exists."
 msgstr ""
 
+msgid "Administrator with email \"{{ value }}\" is already registered"
+msgstr ""
+
+msgid "Administrator with user name \"{{ value }}\" is already registered"
+msgstr ""
+
 msgid "Amount of money should be greater than or equal to zero."
 msgstr ""
 
@@ -547,6 +553,9 @@ msgstr ""
 msgid "Telephone number cannot be longer than {{ limit }} characters"
 msgstr ""
 
+msgid "The \"{{ value }}\" value of \"{{ fieldName }}\" field must be unique"
+msgstr ""
+
 msgid "The amount of money should be {{ limit }} or less."
 msgstr ""