This error occurs when Royal Mail cannot generate a label because a declared item value is zero or outside the accepted range.
Error message
"The ItemValue must range between 0.01 and 999999.99"
What this means
Royal Mail requires all items to have a declared value greater than zero. An item value of 0 or a missing value will cause this error.
How to fix it
Review the item values for all products on the shipment.
Ensure all items have a declared value greater than 0.
Update the item value in the product catalog or on the order.
Regenerate the label.
If the issue continues
Contact support with the RMA ID and a screenshot of the error.