Getting Error "There is an Error in XML Document (2, 2)" Having trouble getting Zip to City State Lookup with USPS WEB API

Question

Trying to get a city and state from a zip5 and I can't seem to get the XML right according to the Error I keep getting "There is an Error in XML Document (2, 2)" when I run it through postman

This is the Service

    private const string BaseURL = "https://secure.shippingapis.com/ShippingAPI.dll";
    private WebClient wsClient = new WebClient();
    public string USPS_UserID = "********";
    public WebTools() { }
    public WebTools(string New_UserID)
    {
        USPS_UserID = New_UserID;
    }
     private byte[] GetDataFromSite(string USPS_Request)
    {


        //Send the request to USPS. 
        byte[] ResponseData = wsClient.DownloadData(USPS_Request);

        return ResponseData;

    }

    public byte[] CityStateLookupRequest(string ZipCode)
    {
        //http://production.shippingapis.com/ShippingAPITest.dll?API=CityStateLookup 

        //  &XML=<CityStateLookupRequest USERID="xxxxxxx"><ZipCode ID= "0"> 

        //  <Zip5>90210</Zip5></ZipCode></CityStateLookupRequest> 

        string strResponse = "", strUSPS = "";

        strUSPS = BaseURL + "?API=CityStateLookup&XML=<CityStateLookupRequest USERID=\"" + USPS_UserID + "\">";

        strUSPS += "<ZipCode ID=\"0\">";

        strUSPS += "<Zip5>" + ZipCode + "</Zip5>";

        strUSPS += "</ZipCode></CityStateLookupRequest>";

        //Send the request to USPS. 

        return GetDataFromSite(strUSPS);

        }
}

}

I blanked out my user id