py27-certbot failing

[Carmel NY]

I have been running py27-certbot from a cron job successfully for months.
Suddenly, it has started to fail. This is the error message:

Traceback (most recent call last):
  File "/usr/local/bin/certbot", line 6, in <module>
    from pkg_resources import load_entry_point
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3147, in <module>
    @_call_aside
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3131, in _call_aside
    f(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3160, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 668, in _build_master
    return cls._build_from_requirements(__requires__)
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 681, in _build_from_requirements
    dists = ws.resolve(reqs, Environment())
  File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 875, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.ContextualVersionConflict: (cryptography 2.0.3 (/usr/local/lib/python2.7/site-packages), Requirement.parse('cryptography>=2.1.4'), set(['PyOpenSSL']))

I have no idea what the problem is. I am hoping that someone might have an
idea.

Thanks!

-- 
Carmel