Certbot生成证书后报错

生成证书的时候报错

Traceback (most recent call last):
File "/bin/certbot", line 9, in <module>
load_entry_point('certbot==1.6.0', 'console_scripts', 'certbot')()
File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 489, in load_entry_point
return get_distribution(dist).load_entry_point(group, name)
File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2852, in load_entry_point
return ep.load()
File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2443, in load
return self.resolve()
File "/usr/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2449, in resolve
module = __import__(self.module_name, fromlist=['__name__'], level=0)
File "/usr/lib/python2.7/site-packages/certbot/main.py", line 2, in <module>
from certbot._internal import main as internal_main
File "/usr/lib/python2.7/site-packages/certbot/_internal/main.py", line 20, in <module>
from certbot._internal import account
File "/usr/lib/python2.7/site-packages/certbot/_internal/account.py", line 18, in <module>
from acme.client import ClientBase # pylint: disable=unused-import
File "/usr/lib/python2.7/site-packages/acme/client.py", line 39, in <module>
requests.packages.urllib3.contrib.pyopenssl.inject_into_urllib3() # type: ignore
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 118, in inject_into_urllib3
_validate_dependencies_met()
File "/usr/lib/python2.7/site-packages/urllib3/contrib/pyopenssl.py", line 160, in _validate_dependencies_met
"'pyOpenSSL' module missing required functionality. "
ImportError: 'pyOpenSSL' module missing required functionality. Try upgrading to v0.14 or newer.

解决方法：pip install --upgrade --force-reinstall 'requests==2.6.0'