If your Drupal commerce store is no longer return shipping rates, you need to upgrade your UPS module. As of November 2024, UPS has deactivated the legacy APIs for shipping rates and your store integration with UPS will not function.
The Drupal 7 module does not have an upgrade available. We do have a functional Drupal 7 Commerce UPS Shipping module available that uses the new Oauth 2.0 security headers.
Access Key Deprecation: https://www.drupal.org/project/commerce_ups/issues/3453280
