Failed to request Let's encrypted certificat : Why?

Dear You, Usally everything is ok, but today (1st August), my certificat is out of date (31 july) and i can't renew in Virtualmin > server configuration > Manage SSL Certificat > Let's encrypted

I asked a new certificat and the answer is: Parsing account key... Parsing CSR... Registering account... Already registered! Verifying autodiscover.cuk.co.il... Traceback (most recent call last): File "/usr/libexec/webmin/webmin/acme_tiny.py", line 235, in main(sys.argv[1:]) File "/usr/libexec/webmin/webmin/acme_tiny.py", line 231, in main signed_crt = get_crt(args.account_key, args.csr, args.acme_dir, args.dns_hook, args.cleanup_hook, log=LOGGER, CA=args.ca) File "/usr/libexec/webmin/webmin/acme_tiny.py", line 184, in get_crt domain, challenge_status)) ValueError: autodiscover.cuk.co.il challenge did not pass: {u'status': u'invalid', u'keyAuthorization': u'Hf18CQ24pBpbWBqO4BFthifvvmFCBgLa8-bsJ44KbYU.JVQGjuCD0e8Fq13I1nCUy-0zKwhquI7igExcfCpiEPA', u'uri': u'https://acme-v01.api.letsencrypt.org/acme/challenge/zh_0-4mHkSR4qhUV2BDr...', u'token': u'Hf18CQ24pBpbWBqO4BFthifvvmFCBgLa8-bsJ44KbYU', u'error': {u'status': 400, u'type': u'urn:acme:error:connection', u'detail': u'DNS problem: NXDOMAIN looking up TXT for _acme-challenge.autodiscover.cuk.co.il"}, u'type': u'dns-01'}