How do I update an SSL certificate in Python?

Question

I am running python 3.9.1 I have some Django Admin Actions which create and then download some PDFs. When running this on my local machine (Windows 10) I have recently started getting the following error message: SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1123)

Any ideas on how I can deal with this? The Django app works perfectly on the server, the problem is only on my local host.

Answer 1

In my case, I was interacting with IoT (Internet of Things) device APIs and had a LetsEncrypt certificate that expired. I downloaded the new LetsEncrypt cert at: https://valid-isrgrootx1.letsencrypt.org/

More explanation:

My error occurred on a Windows Python client requesting API information from an IoT web server. I determined which client certificate was expired by viewing existing certificates dates in Windows:

• Open Powershell as admin, then: Get-Childitem cert:\LocalMachine\root |format-list

The expired cert was owned by LetsEncrypt. More information about the expired cert: https://letsencrypt.org/docs/dst-root-ca-x3-expiration-september-2021/.

In my case, the LetsEncrypt root certificate expired at the end of September and was replaced with the newer cert going forward. To implement the new cert, visit any webpage that uses that certificate from your failing client. In the case of LetsEncrypt, visit their cert demo page at: https://valid-isrgrootx1.letsencrypt.org/, and your certificate store will update automatically.