diff --git a/core/modules/config/lib/Drupal/config/Form/ConfigExportForm.php b/core/modules/config/lib/Drupal/config/Form/ConfigExportForm.php
index 4cf5bcd..ea51439 100644
--- a/core/modules/config/lib/Drupal/config/Form/ConfigExportForm.php
+++ b/core/modules/config/lib/Drupal/config/Form/ConfigExportForm.php
@@ -11,7 +11,7 @@ public function getFormID() {
   }
 
   public function buildForm(array $form, array &$form_state) {
-    $form['#action'] = '/admin/config/development/export-download';
+    $form['#action'] = base_path() . 'admin/config/development/export-download';
     $form['description'] = array(
       '#markup' => '<p>' . t('Use the export button below to download your site configuration.') . '</p>',
     );