I've tried applying some of the following SO answers to an ES server:
However, I always get a SSL certificate authentication error.
curl: (60) SSL certificate problem: self-signed certificate in certificate chain
More details here: https://curl.se/docs/sslcerts.html
curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
Is there a workaround for this?