Webmin + Usermin Per-IP Certificate issues

a CentOS 6.10 based host with the latest Webmin, Virtualmin, Usermin, etc.

I want to use Per-IP cert for Usermin and Webmin access for the different vhosts, but i get the certificate issue (he wants to use the main certificate for the host, not per-ip).
I have another host with centos 7, there is working as needed. I compared the settings, i checked the miniserv config (both for webmin, usermin also), they seems ok, certificates are ok, but still cant “separate” by the request.
A single thing i seen was, when i want to set to “No” at Service Certificates (Server Configuration > SSL Certificate > Service Certificates) i get the following error: " Failed to save service certificates : Service webmin failed" or the same with ursermin when i want to change the usermin one.

Can you help me?
Than you.

Bump? :S
Not enough information?

Got the same issue on another Centos 6.10 VM (all with latest Virtualmin, Webmin, Usermin, etc.).