diff --git a/src/Form/VaultConfigForm.php b/src/Form/VaultConfigForm.php
index 60806a5..9d70728 100644
--- a/src/Form/VaultConfigForm.php
+++ b/src/Form/VaultConfigForm.php
@@ -127,6 +127,7 @@ class VaultConfigForm extends ConfigFormBase {
     $config
       ->set('base_url', $form_state->getValue('base_url'))
       ->set('plugin_auth', $form_state->getValue('plugin_auth'))
+      ->set('lease_ttl_increment', $form_state->getValue('lease_ttl_increment'))
       ->save();
 
     $type = \Drupal::service('plugin.manager.vault_auth');