diff --git a/src/Plugin/Commerce/PaymentGateway/PayoneCreditCard.php b/src/Plugin/Commerce/PaymentGateway/PayoneCreditCard.php
index 2a18510..15d16ba 100644
--- a/src/Plugin/Commerce/PaymentGateway/PayoneCreditCard.php
+++ b/src/Plugin/Commerce/PaymentGateway/PayoneCreditCard.php
@@ -120,24 +120,28 @@ class PayoneCreditCard extends OnsitePaymentGatewayBase implements PayoneCreditC
       '#type' => 'textfield',
       '#title' => $this->t('Merchant ID'),
       '#default_value' => $this->configuration['merchant_id'],
+      '#required' => TRUE,
     ];
 
     $form['portal_id'] = [
       '#type' => 'textfield',
       '#title' => $this->t('Portal ID'),
       '#default_value' => $this->configuration['portal_id'],
+      '#required' => TRUE,
     ];
 
     $form['sub_account_id'] = [
       '#type' => 'textfield',
       '#title' => $this->t('Sub-Account ID'),
       '#default_value' => $this->configuration['sub_account_id'],
+      '#required' => TRUE,
     ];
 
     $form['key'] = [
       '#type' => 'textfield',
       '#title' => $this->t('PAYONE Key'),
       '#default_value' => $this->configuration['key'],
+      '#required' => TRUE,
     ];
     $card_type_map = array_flip(self::creditCardMap());
     $credit_card_types = CreditCard::getTypeLabels();