Seems that you provided bad URL. Try another one, bye.

my input url is an AEM but still getting an error "Seems that you provided bad URL. Try another one, bye.",

Fixed it by editting the preflight function:

def preflight(url, proxy=None, debug=False):
    try:
        http_request(url, proxy=proxy, debug=debug)
    except:
        return True
    else:
        return True

I know that this is not a good fix but it should be fix properly.