When booking with TNT, you may receive the following error on shipments:
"Article invoice value must be greater than zero"
This is due to a lack of value provided on the products in the shipment. The shipment may have an overall value, but TNT require a value on every product in the shipment individually as well. If one or more of your products in a shipment have no value provided, you'll receive this error.
To resolve this, you'll want to ensure that all products passed from your channel contain a value, (even a 0.1 value will suffice). After updating in your channel, if you hit "retry" on the order in Shiptheory, the updated information should pull through.
If you have any issues from there, please feel free to Contact Support