LineAlreadyExists
Example
{
	"code": "LineAlreadyExists",
	"target": "Unknown",
	"details": [
		{
			"code": "LineAlreadyExists",
			"number": 1101,
			"message": "The line to be added has already existed.",
			"description": "Line -0- exists. You can't add an existing line to existing transaction.",
			"faultCode": "Client",
			"helpLink": "http://developer.avalara.com/avatax/errors/LineAlreadyExists",
			"severity": "Error"
		}
	]
}
Explanation

When calling the AddLines API, you must specify the line numbers of the lines you want to add. If you specify a line number that conflicts with an existing line number, you will receive this error.