Let’s Encrypt（certbot）のcronでエラー発生

導入して最初の更新(cron)でエラーが発生

Failed to renew certificate chinaz.org with error: HTTPSConnectionPool(host='acme-v02.api.letsencrypt.org', port=443): Max retries exceeded with url: /directory (Caused by NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection object at 0x7f8a4b76ecf8>: Failed to establish a new connection: [Errno -2] Name or service not known',))
All renewals failed. The following certificates could not be renewed:
  /etc/letsencrypt/live/chinaz.org/fullchain.pem (failure)
1 renew failure(s), 0 parse failure(s)

Googleで検索したら、certbootの名前解決はIPv6が使用されている記事があったので、BINDでIPv6を有効化することで翌々日に改善できたと思う。

# vi /etc/named.conf
-------------------------------------------------------------------------------
listen-on-v6 port 53 { none; };
       ↓
listen-on-v6 port 53 { any; };
-------------------------------------------------------------------------------