You will receive a notification e-mail like the following.
domain.tld: AutoSSL would normally renew this certificate now, but X of the website’s secured domains just failed DCV. To provide you with more time to resolve these problems, AutoSSL will defer the renewal until Dec 20, 2021 at 12:00:00 AM UTC. After that time, AutoSSL will request a replacement certificate that excludes any domains that fail DCV. At the time of this notice, the certificate will expire in 6 days, 21 hours, 13 minutes, and 51 seconds.
This notification is sent because one or more secured domains or sub-domains under your account no longer pass DCV checks. This failure to pass DCV checks can occur due to changes in where the domain's DNS is hosted or changes in where the secured domains resolve. This usually indicates that your DNS servers do not point to our network.
As long as your main domain (YourDomain.com / www.YourDomain.com) does not show in the list of failed DCV checks, then you can safely discard this email warning except if you have subdomains that you wish to renew on that failed DCV check list.
To resolve this immediately, you can ensure that all domains you wish to secure resolve to the server or have their DNS managed by the server. Any domains you do not wish to secure can be excluded as described below (Typically, the warning will sound for webmail.yourdomain , cpanel.yourdomain which is normal and can be safely discarded).
If the domains failing DCV are not corrected or excluded, a new SSL certificate will be automatically issued that excludes all DCV failing domains.