ssl – OpenSSL: tls12_check_peer_sigalg:wrong signature type

So, my first problem started with this python code failing:

import urllib3

http = urllib3.connection.HTTPSConnection("secure.vonage.com")
http.request("GET", "/")

Which gave me:
ssl.SSLError: (SSL: WRONG_SIGNATURE_TYPE) wrong signature type (_ssl.c:1123)

But, actually, I think I’ve “narrowed” it to finding that it fails from openssl:

openssl s_client -connect secure.vonage.com:443

(It says: 140136096142656:error:1414D172:SSL routines:tls12_check_peer_sigalg:wrong signature type:../ssl/t1_lib.c:1145: )

I did do some preliminary searching, and found this: https://wiki.debian.org/ContinuousIntegration/TriagingTips/openssl-1.1.1

But, I tried that (I’m using ubuntu:20.04) and it didn’t work for me..

Can someone tell me how I can make this work/further debug what the problem is?

FWIW, I tried both with www.google.com and both work then. So, it seems clear there’s a problem with secure.vonage.com, but nevertheless, I do still want to connect to vonage. Also, I’m able to connect to secure.vonage.com via the browser.

Thanks!