failed to install pyOpenSSL ubuntu 18

Question

i want to redirect http to https with certbot, i use ubuntu 18, Python version 3.6, but when i command

certbot --nginx -d [my domain] 

is error like this:

    Traceback (most recent call last):
  File "/home/prod/.local/bin/certbot", line 5, in <module>
    from certbot.main import main
  File "/usr/lib/python3/dist-packages/certbot/main.py", line 10, in <module>
    import josepy as jose
  File "/usr/lib/python3/dist-packages/josepy/__init__.py", line 44, in <module>
    from josepy.interfaces import JSONDeSerializable
  File "/usr/lib/python3/dist-packages/josepy/interfaces.py", line 8, in <module>
    from josepy import errors, util
  File "/usr/lib/python3/dist-packages/josepy/util.py", line 4, in <module>
    import OpenSSL
ModuleNotFoundError: No module named 'OpenSSL'

but when i check version openSSL , result like this, openSSL have installed:

     pip3 show pyOpenSSL
Name: pyOpenSSL
Version: 17.5.0
Summary: Python wrapper module around the OpenSSL library
Home-page: https://pyopenssl.org/
Author: The pyOpenSSL developers
Author-email: [email protected]
License: Apache License, Version 2.0
Location: /usr/lib/python3/dist-packages
Requires: 
Required-by: 

when i install pip3.6 install pyOpenSSL, result output like this:

How to fix This ?