Using Centos, but I doubt that matters.
"full" customer, using all the stuff in virtualmin, moves his website to another host, but leaves DNS and Mail here. So, turn off the "Apache" stuff and its all good. Time passes, and the SSL certs that were happily used in Dovecot timeout, since Apache SSL isn't there any more to update them. Dovecot of course doesn't complain, and things are fine, but SSL connections start failing to the dovecot server on that domain. Not all the connections, just some (thats a different problem).
So, if you remove the Apache SSL settings from a virtual domain, should either find a different way of keeping the SSL up to date, or remove it from dovecot.conf. Would be great if Virtualmin would just keep updating the domains SSL cert though.