I had the same problem today. It reported an internal server error, but the certificate is on crt.sh (in fact two are, since I ran it again after making some changes in a vain attempt to avoid the error).
https://crt.sh/?id=13580981
The error looked like this:
2016-03-04 19:58:45,396:DEBUG:acme.client:Received response <Response [500]> (headers: {‘Content-Length’: ‘88’, ‘Expires’: ‘Fri, 04 Mar 2016 19:58:45 GMT’, ‘Server’: ‘nginx’, ‘Connection’: ‘close’, ‘Pragma’: ‘no-cache’, ‘Cache-Control’: ‘max-age=0, no-cache, no-store’, ‘Date’: ‘Fri, 04 Mar 2016 19:58:45 GMT’, ‘Content-Type’: ‘application/problem+json’, ‘Replay-Nonce’: ‘iuT0HW6bJsgtxpAWNWFHZFW19hhjUAo4BMaBPlkeLGY’}): '{“type”:“urn:acme:error:serverInternal”,“detail”:“Error creating new cert”,“status”:500}'
2016-03-04 19:58:45,397:DEBUG:letsencrypt.cli:Exiting abnormally:
Traceback (most recent call last):
File “~/.local/share/letsencrypt/bin/letsencrypt”, line 11, in
sys.exit(main())
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py”, line 1993, in main
return config.func(config, plugins)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py”, line 707, in obtain_cert
_, action = _auth_from_domains(le_client, config, domains, lineage)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/cli.py”, line 475, in _auth_from_domains
lineage = le_client.obtain_and_enroll_certificate(domains)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/client.py”, line 269, in obtain_and_enroll_certificate
certr, chain, key, _ = self.obtain_certificate(domains)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/client.py”, line 252, in obtain_certificate
return self.obtain_certificate_from_csr(domains, csr) + (key, csr)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/letsencrypt/client.py”, line 229, in obtain_certificate_from_csr
authzr)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/acme/client.py”, line 319, in request_issuance
headers={‘Accept’: content_type})
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/acme/client.py”, line 652, in post
return self._check_response(response, content_type=content_type)
File “~/.local/share/letsencrypt/local/lib/python2.7/site-packages/acme/client.py”, line 568, in _check_response
raise messages.Error.from_json(jobj)
Error: urn:acme:error:serverInternal :: The server experienced an internal error :: Error creating new cert