[Geany-Devel] Unable to manage mailing list subscription

[Development]

Greetings,
 I'm attempting to manage my mailing list subscription on the
Geany mailing list, via the web-interface. But when going to
https://lists.geany.org/cgi-bin/mailman/options/devel/development
I'm greeted with a warning, regarding the certificate:

This Connection is Untrusted
...

Technical Details
lists.geany.org uses an invalid security certificate.
The certificate is not trusted because no issuer chain was provided.
(Error code: sec_error_unknown_issuer)

Thank you for all your time, and consideration.

--Chris