[root@PBN_Hieu home]# # Stop Nginx
[root@PBN_Hieu home]# service nginx stop
Stopping nginx: # Install Let's Encrypt
cd /opt/letsencrypt
                                                           [  OK  ]
[root@PBN_Hieu home]# # Install Let's Encrypt
[root@PBN_Hieu home]# cd /opt/letsencrypt
[root@PBN_Hieu letsencrypt]# ./letsencrypt-auto certonly --standalone
# Start Nginx
service nginx start/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
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Please enter in your domain name(s) (comma and/or space separated)  (Enter 'c'
to cancel): Obtaining a new certificate
An unexpected error occurred:
The request message was malformed :: Error creating new authz :: Invalid character in DNS name
Please see the logfiles in /var/log/letsencrypt for more details.
[root@PBN_Hieu letsencrypt]# service nginx start