diff --git a/src/Authentication/Passwords/ValidationRules.php b/src/Authentication/Passwords/ValidationRules.php
index 087b15a30..2ad59c87d 100644
--- a/src/Authentication/Passwords/ValidationRules.php
+++ b/src/Authentication/Passwords/ValidationRules.php
@@ -102,10 +102,9 @@ protected function buildUserFromData(array $data = []): User
      */
     protected function prepareValidFields(): array
     {
-        $config   = config('Auth');
-        $fields   = array_merge($config->validFields, $config->personalFields);
-        $fields[] = 'password';
+        $config = config('Auth');
+        $fields = array_merge($config->validFields, $config->personalFields, ['email', 'password']);
 
-        return $fields;
+        return array_unique($fields);
     }
 }
diff --git a/tests/Controllers/RegisterTest.php b/tests/Controllers/RegisterTest.php
index 3b8e73afe..630c13b38 100644
--- a/tests/Controllers/RegisterTest.php
+++ b/tests/Controllers/RegisterTest.php
@@ -82,6 +82,16 @@ public function testRegisterActionSuccess(): void
         $this->assertTrue($user->active);
     }
 
+    public function testRegisterActionSuccessWithNoEmailLogin(): void
+    {
+        /** @var Auth $config */
+        $config = config('Auth');
+        // Use `username` for login
+        $config->validFields = ['username'];
+
+        $this->testRegisterActionSuccess();
+    }
+
     public function testRegisterTooLongPasswordDefault(): void
     {
         $result = $this->withSession()->post('/register', [