Secure Sentora Domains with Let's Encrypt

[hrace009]

i have follow everything, but when on browser i always got this
   

and when i run this command

Code:

./letsencrypt-auto certonly --webroot --webroot-path /etc/sentora/panel --renew-by-default --email me@email.com --text --agree-tos -d panel.mydomain.com

it always failed

Code:

[root@panel letsencrypt]# ./letsencrypt-auto certonly --webroot --webroot-path /etc/sentora/panel --renew-by-default --email myemail@myemail.com --text --agree-tos -d panel.mydomain.com
/root/.local/share/letsencrypt/lib/python2.6/site-packages/cryptography/__init__.py:26: DeprecationWarning: Python 2.6 is no longer supported by the Python core team, please upgrade your Python. A future version of cryptography will drop support for Python 2.6
 DeprecationWarning
Failed authorization procedure. panel.mydomain.com (http-01): urn:acme:error:connection :: The server could not connect to the client to verify the domain :: Could not connect to http://panel.mydomain.com/.well-known/acme-challenge/R8r4U5m18WFzD8hWZp7V0BrWnZFayA6W_uZtOLXT9U8

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

  Domain: panel.mydomain.com
  Type:   connection
  Detail: Could not connect to
  http://panel.mydomain.com/.well-known/acme-challenge/R8r4U5m18WFzD8hWZp7V0BrWnZFayA6W_uZtOLXT9U8

  To fix these errors, please make sure that your domain name was
  entered correctly and the DNS A 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.

iam sure everything has been set, and i can ping my panel.mydomain.com to the right IP on my VPS

-------------------- UPDATE 2:28 AM GMT+7 --------------------------------------
seems i almost found the right way. but i just reach limit, so i must wait for a week