ssl.CertificateError: hostname '' doesn't match ''


I have a parent domain, and two sub domains. Previously, all have been auto renewing letsencrypt ssl certs without issue. I’m running Virtualmin version 6.01.gpl.

Now, the two sub domains are fine, but the parent ( keeps getting an error message, referencing one of the sub domains:
apache config:

DNS is setup correct, I’ve checked the letsencrypt settings for all 3 and they have the correct address (their own) in. I’ve tried typing it in manually, and choosing the default address option but the failure always come back the same. Any idea where I can check to get to the bottom of this?



The way I get around this is to disable the site (which I can, as it’s just a home project), and then renew the cert on, then re-enable

Obviously not the kind of hack you can roll out in a production environment,.

disabling the site and renewing doesn’t even work now, is this a recognised issue or am I special?