let's encrpt error msg

Hi I got an error on a testing site for ssl, this site has "nothing", just a wordpress install, nothing modify. please help

Parsing account key... Parsing CSR... Registering account... Already registered! Verifying www.test.orderlastminute.com... Wrote file to /home/test/public_html/.well-known/acme-challenge/8_-VpTdjLDWmopekKB-E_pcQow2z_to9bb3ELnf0ed8, but couldn't download http://www.test.orderlastminute.com/.well-known/acme-challenge/8_-VpTdjL... Traceback (most recent call last): File "/usr/share/webmin/webmin/acme_tiny.py", line 202, in main(sys.argv[1:]) File "/usr/share/webmin/webmin/acme_tiny.py", line 198, in main signed_crt = get_crt(args.account_key, args.csr, args.acme_dir, log=LOGGER, CA=args.ca) File "/usr/share/webmin/webmin/acme_tiny.py", line 153, in get_crt domain, challenge_status)) ValueError: www.test.orderlastminute.com challenge did not pass: {u'status': u'invalid', u'validationRecord': [{u'addressesResolved': [], u'url': u'http://www.test.orderlastminute.com/.well-known/acme-challenge/8_-VpTdjL...', u'hostname': u'www.test.orderlastminute.com', u'addressesTried': [], u'addressUsed': u'', u'port': u'80'}], u'keyAuthorization': u'8_-VpTdjLDWmopekKB-E_pcQow2z_to9bb3ELnf0ed8.B97r49jPq6p0h4ivv6NE-cy8AaDEU2uJPRygb8EdHnY', u'uri': u'https://acme-v01.api.letsencrypt.org/acme/challenge/TzzNOtY6SOIS1_exB2xc...', u'token': u'8_-VpTdjLDWmopekKB-E_pcQow2z_to9bb3ELnf0ed8', u'error': {u'status': 400, u'type': u'urn:acme:error:connection', u'detail': u'DNS problem: NXDOMAIN looking up A for www.test.orderlastminute.com'}, u'type': u'http-01'}