TaxpayerNumberIsRequired
Example
{
	"code": "TaxpayerNumberIsRequired",
	"target": "Unknown",
	"details": [
		{
			"code": "TaxpayerNumberIsRequired",
			"number": 1714,
			"message": "TaxpayerIdNumber is required.",
			"description": "TaxpayerIdNumber is required if the address provided is inside the US.",
			"faultCode": "Client",
			"helpLink": "http://developer.avalara.com/avatax/errors/TaxpayerNumberIsRequired",
			"severity": "Error"
		}
	]
}
Explanation

For United States addresses, a TaxpayerIdNumber must be provided.