Resolved

I was able to check the error here and it appears that this has been a reported issue with our Shipping team. Looking at all reported error by merchants it seems this is affecting all merchant using USPS return label generation.

It has been submitted to our developers for further investigation but at the moment we haven't yet a turnaround time when it will be expected to address the issue. Alternatively, you can attempt to purchase a non-USPS return label, or purchase a USPS label off platform. We are now coordinating with the USPS to address this promptly.

Resolved

In Normal Operation, some trackings may not synchronize with the correct courier on shopify, please report this so that we can correct it.-Lucas