A entry for www fails for PowerDNS

[Spacedust]

With errors like this:

  File "/root/.local/share/letsencrypt/lib/python2.7/site-packages/certbot/client.py", l             ine 246, in obtain_certificate
    self.config.allow_subset_of_names)
  File "/root/.local/share/letsencrypt/lib/python2.7/site-packages/certbot/auth_handler.             py", line 74, in get_authorizations
    self._respond(resp, best_effort)
  File "/root/.local/share/letsencrypt/lib/python2.7/site-packages/certbot/auth_handler.             py", line 131, in _respond
    self._poll_challenges(chall_update, best_effort)
  File "/root/.local/share/letsencrypt/lib/python2.7/site-packages/certbot/auth_handler.             py", line 195, in _poll_challenges
    raise errors.FailedChallenges(all_failed_achalls)
FailedChallenges: Failed authorization procedure. www.pieniadze.xxx.pl (http-01):              urn:acme:error:connection :: The server could not connect to the client to verify the do             main :: DNS problem: NXDOMAIN looking up A for www.pieniadze.xxx.pl