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Receiving an “ERROR: Field not found” when installing the extension can be caused by adding the custom sales order fields incorrectly, or failing to add them altogether.
Click Save.
Ensuring Rates can be used at Checkout
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Navigate to Lists > Accounting > Shipping Items.
From the list, locate all Shipping Rates you want returned at the time of checkout. Repeat this for each Shipping Item necessary.
Click Edit.
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