PyMongo [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate

Question

I'm using Python 3.9.5 and PyMongo 3.11.4. The version of my MongoDB database is 4.4.6. I'm using Windows 8.1

I'm learning MongoDB and I have a cluster set up in Atlas that I connect to. Whenever I try to insert a document into a collection, a ServerSelectionTimeoutError is raised, and inside its parentheses there are several [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate.

Troubleshooting TLS Errors in the PyMongo docs weren't too much help as they only provided tips for Linux and macOS users.

It's worth mentioning that if I set tlsAllowInvalidCertificates=True when initializing my MongoClient, everything works fine. That sounds insecure, and while I am working on a small project, I would still like to develop good habits and not override any security measures in place, so I'm hoping there is an alternative to that.

From all the searching I've done, I'm guessing that I'm missing certain certificates, or that Python can't find them. I've looked into the certifi package, but this part of the docs makes it seem that should only be necessary if I'm using Python 2.x, which I'm not.

So yeah, I'm kind of stuck right now.

Answer 1

Well, I eventually decided to install certifi and it worked.

client = MongoClient(CONNECTION_STRING, tlsCAFile=certifi.where())

Wish the docs were a bit clearer on this, but maybe I just didn't look hard enough.

Answer 2

In Flask server I solved by using:

import certifi

app = Flask(__name__)
app.config['MONGO_URI'] = 
'mongodb+srv://NAME:<PWD><DBNAME>.9xxxx.mongodb.net/<db>? retryWrites=true&w=majority' 
mongo = PyMongo(app,tlsCAFile=certifi.where())
collection_name = mongo.db.collection_name