Works with urrlib.request but doesn't work with requests

The issue seems to be with how the host is handling ssl. Newer versions of requests uses certifi which in your case is having issues with the host server. I downgraded requests to an earlier version and it worked. (2.1.0). You can fix the version in your requirements.txt and it should work with any python version.

https://requests.readthedocs.io/en/master/user/advanced/#ca-certificates

Before version 2.16, Requests bundled a set of root CAs that it trusted, sourced from the Mozilla trust store. 
The certificates were only updated once for each Requests version. When certifi was not installed, this led to extremely out-of-date certificate bundles when using significantly older versions of Requests.

For the sake of security we recommend upgrading certifi frequently!