$ pip list
Package          Version
---------------- -------------
attrs            19.3.0
certifi          2020.4.5.2
cffi             1.14.0
chardet          3.0.4
cryptography     2.9.2
idna             2.9
pip              20.1.1
pyasn1           0.4.8
pyasn1-modules   0.2.8
pycparser        2.20
pymongo          3.11.0b2.dev0
pyOpenSSL        19.1.0
requests         2.23.0
service-identity 18.1.0
setuptools       47.3.0
six              1.15.0
urllib3          1.25.9
wheel            0.34.2
(venv3.8)
$ python tools/ocsptest.py --host google.com
Traceback (most recent call last):
  File "tools/ocsptest.py", line 56, in <module>
    main()
  File "tools/ocsptest.py", line 53, in main
    check_ocsp(args.host, args.port, args.ca_file)
  File "tools/ocsptest.py", line 39, in check_ocsp
    s = ctx.wrap_socket(s, server_hostname=host)
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\pymongo\pyopenssl_context.py", line 295, in wrap_socket
    ssl_conn.do_handshake()
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\pymongo\pyopenssl_context.py", line 110, in do_handshake
    return self._call(super(_sslConn, self).do_handshake, *args, **kwargs)
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\pymongo\pyopenssl_context.py", line 101, in _call
    return call(*args, **kwargs)
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\OpenSSL\SSL.py", line 1934, in do_handshake
    self._raise_ssl_error(self._ssl, result)
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\OpenSSL\SSL.py", line 1671, in _raise_ssl_error
    _raise_current_error()
  File "C:\cygwin\home\Administrator\venv3.8\lib\site-packages\OpenSSL\_util.py", line 54, in exception_from_error_queue
    raise exception_type(errors)
OpenSSL.SSL.Error: [('SSL routines', 'tls_process_server_certificate', 'certificate verify failed')]
(venv3.8)