DNS restart error due to dkim selector

Not setting Selector in opendkim config file leaves selector empty and DNS record like ._domainkey, which is invalid to DNS. Took me a while to find it is not related to theme or other things because it looked like I should be able to modify the used selector key from Virtualmin, Email settings, Domainkey Identified Mail. You have to set the Selector in /etc/opendkim.conf



That's odd, because the Virtualmin UI should prevent an empty selector from being entered.

How did you enable DKIM exactly?