Troubleshooting

"Test Connection" Fails

1. Double-check the Client ID/Secret were copied without extra spaces.
2. Confirm the Environment dropdown (Production vs. Sandbox) matches the credentials you generated - sandbox credentials will not authenticate against production.
3. For FedEx, confirm your account number is entered - some FedEx endpoints require it even for the OAuth token step.
4. Enable Debug mode (Advanced tab) and check the logged request/response for the carrier's exact error message.

Label Purchase Rejected

1. Validate your shipper address on the Shipper address tab - an invalid origin address fails every label purchase.
2. Confirm the selected package type is actually supported by the chosen service (see USPS package-type validation).
3. Confirm the product(s) on the order have weight and dimensions set - carriers reject packages with no size.

Live Rates Not Showing at Checkout

1. Confirm the carrier is Enabled on its settings tab and Test Connection succeeds.
2. Confirm the shipping method was added to the relevant shipping zone under WooCommerce → Settings → Shipping.
3. Check that the cart's destination address is within a zone where the method is enabled.
4. Rate results are cached for 30 minutes per unique cart - change the cart contents or wait for the cache to expire when testing rate changes.

Tracking Not Updating

1. Confirm the shiplabel_sync_tracking_statuses cron event is scheduled: wp cron event list | grep shiplabel.
2. WP-Cron only fires on site visits by default - on low-traffic stores, set up a real system cron hitting wp-cron.php.
3. If using the tracking webhook, confirm the webhook secret in your carrier/integration matches the one shown on the Advanced tab exactly.