letsencrypt生成证书失败

letsencrypt生成证书失败了, 各位大佬有什么解决方法吗

# ./certbot-auto certonly --nginx -d test0.xxxxxx.com 

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator nginx, Installer nginx
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for test0.xxxxxx.com
Waiting for verification...
Challenge failed for domain test0.xxxxxx.com
http-01 challenge for test0.xxxxxx.com
Cleaning up challenges
Some challenges have failed.

IMPORTANT NOTES:
 - The following errors were reported by the server:

   Domain: test0.xxxxxx.com
   Type:   connection
   Detail: Fetching
   http://test0.xxxxxx.com/.well-known/acme-challenge/ndb-3b0YR_64k7KUSdvCN9BXnVjnRBg-YW_ihjpxXUU:
   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.