I have webmin and virtualmin running on 192.168.80.20 cpanel.manjot.net . I have a virtual server in virtualmin for manjot.net and when I enable ssl for manjot.net. The certificate for cpanel.manjot.net return with the certificate of manjot.net virtual server, instead of certificate I set in webmin but working fine when accessing via ip address 192.168.80.20:10000
And, you shouldn’t mess around with the Webmin SSL configuration. Just let Virtualmin handle it. When you create a Virtualmin domain and setup an SSL certificate for it, Webmin will automatically serve that certificate when connecting to Webmin on that domain (Usermin likewise).
Please see these recent discussions which are related to the issue you mention:
I always create a virtual server with the same domain name I use as hostname - (e.g. vps01.indiax.com), apply SSL to it (mostly via Let’s Encrypt) and then use the “Copy to Webmin” etc. group of buttons to apply that SSL to ports 10000, 20000, Postfix, Dovecot at al.
I would be happy to help you in any way I can, bro! Your community is doing a great service to the nation.