url: https://json.schedulesdirect.org/20141201/token
imho the message is confusing. My username was valid but I sent the wrong password.
{
"response": "INVALID_USER",
"code": 4003,
"serverID": "20141201.web.1",
"message": "Invalid username or token has expired.",
"datetime": "2016-11-25T03:41:18Z"
}