Tax rate field error on order import

Hello,

I am running into below error while importing orders from a shopping cart. I do not have control over the mapping between shopping cart and NetSuite Sales Order. What can I do in NetSuite to fix this error?

You do not have permissions to set a value for element taxrate due to one of the following reasons:

1)The field is read-only;

2) An associated feature is disabled;

3) The field is available either when a record is created or updated, but not in both
cases.

Tax rate field is read only on the form and I can’t make not read only in the form customization.

I appreciate you taking time to read my question.

Thanks,