When sending orders to USPS from your Shiptheory, it's important to note that the weight value for the shipment will be sent to USPS with the unit value of Pounds and Ounces (LBS and Oz)

As such, when using USPS, you'll want to make sure that the weight passed from your channel is already in Pounds and Ounces rather than KG to ensure that there is no confusion with the weight sent through.

If you have any issues, please Contact Support