I have updated my line of code for String_url in the downloader code and replace it with
string _url = "https://cloud.openalpr.com/api/search/group?topn=5000&start=" + str_StartDate + "T" + str_StartHours + ":" + str_StartMinutes + ":31" + str_UTC_Offset + ":00&end=" + str_EndDate + "T" +...