SSL Handshake issue with Pymongo on Python3

Solved the problem with this change:

client = pymongo.MongoClient(uri, ssl_cert_reqs=ssl.CERT_NONE)

The section Troubleshooting TLS Errors of the PyMongo offical document `TLS/SSL and PyMongo introduces the issue as below.

TLS errors often fall into two categories, certificate verification failure or protocol version mismatch. An error message similar to the following means that OpenSSL was not able to verify the server’s certificate:

[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed

This often occurs because OpenSSL does not have access to the system’s root certificates or the certificates are out of date. Linux users should ensure that they have the latest root certificate updates installed from their Linux vendor. macOS users using Python 3.6.0 or newer downloaded from python.org may have to run a script included with python to install root certificates:

open "/Applications/Python <YOUR PYTHON VERSION>/Install Certificates.command"

Users of older PyPy and PyPy3 portable versions may have to set an environment variable to tell OpenSSL where to find root certificates. This is easily done using the certifi module from pypi:

$ pypy -m pip install certifi$ export SSL_CERT_FILE=$(pypy -c "import certifi; print(certifi.where())")

You can try to follow the description above to fix your issue, which seems to be for Linux and Mac Users. On Windows, I can not reproduce your issue in Python 3.7 and 3.6. If you have any concern, please feel free to let me know.

Faced the same issue when trying to connect mongodb from Digital Ocean,Solved by using this function with params in MongoClient:

def get_client(host,port,username,password,db):      return MongoClient('mongodb://{}:{}/'.format(host,port),                         username=username,                         password=password,                         authSource=db,                         ssl=True,ssl_cert_reqs=ssl.CERT_NONE)client = get_client("host-ip","port","username","password","db-name")