Here are a few steps for initial troubleshooting of your Checkout module:
- Reset the MBO module ("PrestaShop Marketplace in your Back Office") via the module manager.
- Reset the PrestaShop Checkout module (also via the module manager).
- Clear the store cache (go to Advanced Settings > Performance and click on "Clear cache").
- Reconnect your PayPal account (via the Checkout module configuration page).
Once these steps are completed, test the checkout process again. If the problem persists, contact us for more advanced diagnostics.