ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED]

[cragkhit]

Hi. Thanks a lot for this useful script. I tried to set it up on my macOS Catalina. I used the virtual environment by following your steps. The requirements have been installed. When I'm running the main.py using python3 main.py, I got the ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] like the error log below. How to fix it?

Python version

% python
Python 3.7.3 (default, Nov 15 2019, 04:04:52)
[Clang 11.0.0 (clang-1100.0.33.16)] on darwin

Error log

Traceback (most recent call last):
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1317, in do_open
    encode_chunked=req.has_header('Transfer-encoding'))
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 1229, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 1275, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 1224, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 1016, in _send_output
    self.send(msg)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 956, in send
    self.connect()
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/http/client.py", line 1392, in connect
    server_hostname=server_hostname)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/ssl.py", line 412, in wrap_socket
    session=session
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/ssl.py", line 853, in _create
    self.do_handshake()
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/ssl.py", line 1117, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main.py", line 38, in <module>
    books = pd.read_excel(table_url)
  File "/Volumes/Transcend2TB/Books/springer_free_books/.venv/lib/python3.7/site-packages/pandas/io/excel/_base.py", line 304, in read_excel
    io = ExcelFile(io, engine=engine)
  File "/Volumes/Transcend2TB/Books/springer_free_books/.venv/lib/python3.7/site-packages/pandas/io/excel/_base.py", line 824, in __init__
    self._reader = self._engines[engine](self._io)
  File "/Volumes/Transcend2TB/Books/springer_free_books/.venv/lib/python3.7/site-packages/pandas/io/excel/_xlrd.py", line 21, in __init__
    super().__init__(filepath_or_buffer)
  File "/Volumes/Transcend2TB/Books/springer_free_books/.venv/lib/python3.7/site-packages/pandas/io/excel/_base.py", line 342, in __init__
    filepath_or_buffer = BytesIO(urlopen(filepath_or_buffer).read())
  File "/Volumes/Transcend2TB/Books/springer_free_books/.venv/lib/python3.7/site-packages/pandas/io/common.py", line 141, in urlopen
    return urllib.request.urlopen(*args, **kwargs)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 222, in urlopen
    return opener.open(url, data, timeout)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 525, in open
    response = self._open(req, data)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 543, in _open
    '_open', req)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 503, in _call_chain
    result = func(*args)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1360, in https_open
    context=self._context, check_hostname=self._check_hostname)
  File "/Library/Developer/CommandLineTools/Library/Frameworks/Python3.framework/Versions/3.7/lib/python3.7/urllib/request.py", line 1319, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)>

[jstnmchl]

I appear to be getting the same error when running the script on a mac (macOS Mojave). Error log is below.

Error Log
Traceback (most recent call last):
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1318, in do_open
encode_chunked=req.has_header('Transfer-encoding'))
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1239, in request
self._send_request(method, url, body, headers, encode_chunked)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1285, in _send_request
self.endheaders(body, encode_chunked=encode_chunked)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1234, in endheaders
self._send_output(message_body, encode_chunked=encode_chunked)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1026, in _send_output
self.send(msg)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 964, in send
self.connect()
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/http/client.py", line 1400, in connect
server_hostname=server_hostname)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 407, in wrap_socket
_context=self, _session=session)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 814, in init
self.do_handshake()
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 1068, in do_handshake
self._sslobj.do_handshake()
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/ssl.py", line 689, in do_handshake
self._sslobj.do_handshake()
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:777)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "main.py", line 38, in
books = pd.read_excel(table_url)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/io/excel/_base.py", line 304, in read_excel
io = ExcelFile(io, engine=engine)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/io/excel/_base.py", line 824, in init
self._reader = self._enginesengine
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/io/excel/_xlrd.py", line 21, in init
super().init(filepath_or_buffer)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/io/excel/_base.py", line 342, in init
filepath_or_buffer = BytesIO(urlopen(filepath_or_buffer).read())
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/io/common.py", line 141, in urlopen
return urllib.request.urlopen(*args, **kwargs)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 223, in urlopen
return opener.open(url, data, timeout)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 526, in open
response = self._open(req, data)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 544, in _open
'_open', req)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 504, in _call_chain
result = func(*args)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1361, in https_open
context=self._context, check_hostname=self._check_hostname)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/urllib/request.py", line 1320, in do_open
raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:777)>

[chaosAD]

Read this: https://stackoverflow.com/questions/50236117/scraping-ssl-certificate-verify-failed-error-for-http-en-wikipedia-org

[arn4]

If you can't download with that solution, here is the code that solved the problem for me https://stackoverflow.com/questions/44649449/brew-installation-of-python-3-6-1-ssl-certificate-verify-failed-certificate/44649450#44649450

[jstnmchl]

Fix from @chaosAD worked for me. Created PR (#75) to add that link and link from @arn4 to troubleshooting section of README.