在通过certbot获取证书时, 总提示失败, 在防火墙中开了80和443的访问了. 错误如下:

http-01 challenge for ***.com.cn
Using the webroot path /var/lib/letsencrypt for all unmatched domains.
Waiting for verification...
Challenge failed for .com.cn
http-01 challenge for.com.cn
Cleaning up challenges
Some challenges have failed.

IMPORTANT NOTES:

• The following errors were reported by the server:

  Domain: .com.cn
  Type: connection
  Detail: Fetching
  http://com.cn/.well-known/acme-challenge/-19M8UVEft2lX_3GDt3YS-Wj-eaJR2imJIqBoj7JBDY:
  Timeout during connect (likely firewall problem)

  To fix these errors, please make sure that your domain name was
  entered correctly and the DNS A/AAAA record(s) for that domain
  contain(s) the right IP address. Additionally, please check that
  your computer has a publicly routable IP address and that no
  firewalls are preventing the server from communicating with the
  client. If you're using the webroot plugin, you should also verify
  that you are serving files from the webroot path you provided.