The TaxType code error occurs when the Export Codes assigned to your GST Types in Workbench do not match a valid TaxType used in Xero.
To resolve this issue, review the GST Types in Workbench and update their Export Codes so they correspond to the appropriate Xero TaxType codes for your country.
A list of valid Xero TaxType codes can be found here:
https://developer.xero.com/documentation/api/accounting/types#report-tax-types
For example, Xero Australia and New Zealand use specific TaxType codes. The Export Code assigned to each GST Type in Workbench must match one of these valid Xero TaxType codes.
