Let's Encrypt renewals lead to "504: Gateway Time-out" error

Hello everybody,

I noticed today that I am unable to renew Let's Encrypt certificates. It happens on several (Debian) servers, am I alone ? Here is the outup :

Requesting a certificate for virtualserver from Let's Encrypt .. .. request failed : Failed to request certificate : Parsing account key... Parsing CSR... Registering account... Traceback (most recent call last): File "/usr/share/webmin/webmin/acme_tiny.py", line 235, in main(sys.argv[1:]) File "/usr/share/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/share/webmin/webmin/acme_tiny.py", line 99, in get_crt "agreement": "https://letsencrypt.org/documents/LE-SA-v1.1.1-August-1-2016.pdf", File "/usr/share/webmin/webmin/acme_tiny.py", line 56, in _send_signed_request protected["nonce"] = urlopen(CA + "/directory").headers['Replay-Nonce'] File "/usr/lib/python2.7/urllib2.py", line 154, in urlopen return opener.open(url, data, timeout) File "/usr/lib/python2.7/urllib2.py", line 437, in open response = meth(req, response) File "/usr/lib/python2.7/urllib2.py", line 550, in http_response 'http', request, response, code, msg, hdrs) File "/usr/lib/python2.7/urllib2.py", line 475, in error return self._call_chain(*args) File "/usr/lib/python2.7/urllib2.py", line 409, in _call_chain result = func(*args) File "/usr/lib/python2.7/urllib2.py", line 558, in http_error_default raise HTTPError(req.get_full_url(), code, msg, hdrs, fp) urllib2.HTTPError: HTTP Error 504: Gateway Time-out