Websites are failing to use the LetsEncrypt SSL certificate generated from "SSL Encryption" section on subdomains specified

Hi All
Refer to this topic too -
I’m having the same problems. I’m on the latest version and am using ubuntu 18.04.1 as the base.
I have used one of my websites that I’m hosting as a reference. Basically the methodology I used was this:
Old Webserver(Cpanel) -> Create full backup -> migrate backup into Virtualmin
I thought everything was ok, however I’m having two issues - although dealing with just this one here, will open another topic for the other soon.

So after migrating the server, everything looked ok. I then went to enable ssl, and was trying to ensure wildcards were supported, but this doesn’t seem to be possible from the UI. However I went in and specified the domains and sub-domains to be included. Strange though, if going into the base domain(url) the certificate is correct, however going into webmail.domain.zzz it seems not to picking up the correct certificate:
Current certificate in virtualmin:
Letsencrypt section:
Certificate on base domain: - which is correct:
Certificate on webmail.basedomain.zzz - which is not correct:
Also I checked the mail settings and this is what I found:
SMTP which is correct:
POP which isn’t corret:

So I’m really confused, and trying to find a solution. Hopefully we have some virtualmin guru’s out there that can point me in the right direction…