On registration, KeyError: 'Directory field not found'

[exarkun]

Using 0.16.0 and acme 0.39.0, I get this behavior:

2019-11-01 23:21:32,619:DEBUG:simp_le:1522: ('-v', '-d', '... DOMAIN', '--default_root', '/var/lib/acme/acme-challenges', '--valid_min', '2592000', '--email', '... EMAIL ...', '-f', 'account_reg.json', '-f', 'account_key.json', '-f', 'full.pem', '-f', 'fullchain.pem', '\
-f', 'key.pem', '--server', 'https://acme-staging.api.letsencrypt.org/directory') parsed as Namespace(account_key_public_exponent=65537, account_key_size=4096, ca_bundle=None, cert_key_size=4096, default_root='/var/lib/acme/acme-challenges', email='... EMAIL ...', help=\
False, integration_test=False, ioplugins=['account_reg.json', 'account_key.json', 'full.pem', 'fullchain.pem', 'key.pem'], reuse_key=False, revoke=False, server='https://acme-staging.$
pi.letsencrypt.org/directory', test=False, user_agent='simp_le/0.16.0', valid_min=2592000, verbose=True, version=False, vhosts=[Vhost(name='... DOMAIN ...', root=None)])
2019-11-01 23:21:32,620:DEBUG:simp_le:372: Loading account_reg.json
2019-11-01 23:21:32,620:DEBUG:simp_le:372: Loading account_key.json
2019-11-01 23:21:32,620:DEBUG:simp_le:372: Loading full.pem
2019-11-01 23:21:32,621:DEBUG:simp_le:372: Loading fullchain.pem
2019-11-01 23:21:32,621:DEBUG:simp_le:372: Loading key.pem
2019-11-01 23:21:32,622:DEBUG:simp_le:1315: Existing SANs: [], new: ['... DOMAIN ...']
2019-11-01 23:21:32,622:DEBUG:simp_le:1405: Computed roots: {'... DOMAIN ...': '/var/lib/acme/acme-challenges'}
2019-11-01 23:21:32,622:INFO:simp_le:1323: Generating new account key
2019-11-01 23:21:33,185:DEBUG:acme.client:1104: Sending GET request to https://acme-staging.api.letsencrypt.org/directory.
2019-11-01 23:21:33,187:DEBUG:urllib3.connectionpool:813: Starting new HTTPS connection (1): acme-staging.api.letsencrypt.org:443
2019-11-01 23:21:33,749:DEBUG:urllib3.connectionpool:393: https://acme-staging.api.letsencrypt.org:443 "GET /directory HTTP/1.1" 200 704
2019-11-01 23:21:33,750:DEBUG:acme.client:1145: Received response:
HTTP 200
Server: nginx
Date: Fri, 01 Nov 2019 23:21:33 GMT
Content-Type: application/json
Content-Length: 704
Connection: keep-alive
Cache-Control: public, max-age=0, no-cache
Replay-Nonce: 0001DMUZu_OzJSYWCoI5b8Zy-PYUADWB34v436ngo2Yy7mI
X-Frame-Options: DENY
Strict-Transport-Security: max-age=604800
{
  "bL-jcLYHmRA": "https://community.letsencrypt.org/t/adding-random-entries-to-the-directory/33417",
  "key-change": "https://acme-staging.api.letsencrypt.org/acme/key-change",
  "meta": {
    "caaIdentities": [
      "letsencrypt.org"
    ],
    "terms-of-service": "https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf",
    "website": "https://letsencrypt.org/docs/staging-environment/"
  },
  "new-authz": "https://acme-staging.api.letsencrypt.org/acme/new-authz",
  "new-cert": "https://acme-staging.api.letsencrypt.org/acme/new-cert",
  "new-reg": "https://acme-staging.api.letsencrypt.org/acme/new-reg",
  "revoke-cert": "https://acme-staging.api.letsencrypt.org/acme/revoke-cert"
}
2019-11-01 23:21:33,750:INFO:simp_le:1353: By using simp_le, you implicitly agree to the CA's terms of service: https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf
Traceback (most recent call last):
  File ".../lib/python3.7/site-packages/acme/messages.py", line 249, in __getitem__
    return self._jobj[self._canon_key(name)]
KeyError: 'newAccount'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File ".../lib/python3.7/site-packages/simp_le.py", line 1565, in main
    return main_with_exceptions(cli_args)
  File ".../lib/python3.7/site-packages/simp_le.py", line 1549, in main_with_exceptions
    persist_new_data(args, existing_data)
  File ".../lib/python3.7/site-packages/simp_le.py", line 1408, in persist_new_data
    args, existing_data.account_key, existing_data.account_reg)
  File ".../lib/python3.7/site-packages/simp_le.py", line 1357, in registered_client
    client.new_account(new_reg)
  File ".../lib/python3.7/site-packages/acme/client.py", line 604, in new_account
    response = self._post(self.directory['newAccount'], new_account)
  File ".../lib/python3.7/site-packages/acme/messages.py", line 251, in __getitem__
    raise KeyError('Directory field not found')
KeyError: 'Directory field not found'
Unhandled error has happened, traceback is above
Debugging tips: -v improves output verbosity. Help is available under --help.

Instead, I expected a Let's Encrypt account to be registered and then a certificate to be issued.