"code": "NexusParentDateMismatch",
	"target": "Unknown",
	"details": [
			"code": "NexusParentDateMismatch",
			"number": 159,
			"message": "To declare nexus in a city or local jurisdiction, you must also declare nexus in the state or country.",
			"description": "Please ensure that the dates for your nexus declaration match with the dates for the nexus declaration at the state or country level.  Affected nexus: JurisTypeId: -3-, JurisName: -4-, EffectiveDate: -8-, EndDate: -9- has conflicting effective dates with its parent in Country: -0-, Region: -1-.",
			"faultCode": "Client",
			"helpLink": "",
			"severity": "Error"

This indicates that you declared nexus on a date when that nexus was not available in the state or country. When you declare that your company has nexus in a particular city or local jurisdiction, AvaTax checks to make sure that nexus was in existence in that jurisdiction's state or country on the dates you specified.

Because tax authorities create and change their tax rules periodically, some locations are only availble for nexus declarations on some dates.