Thanks cPanelLauren!
1) Sorry, I was not clear - when I referred to the domain being renewed I meant the domain name registration being renewed by the domain owner, not to the AutoSSL cert being renewed.
From what I can tell, it looks like the domain name owner allowed the domain name registration to lapse for about 6 days. During this time AutoSSL was running its usual nightly checks and of course DCV failed because during those 6 expired days the domain name was reassigned to some other temporary IP by the domain registrar.
About 6 days after the domain name expired, the owner renewed the domain name registration. We had not removed the site or the zone file from our server during this period, so once the domain name registration was renewed, the original IP settings kicked back in and the site came back online same as before.
It has now been about a week or slightly longer since the domain name registration was renewed, so the live website IP should already have propagated.
But AutoSSL is still giving the same error when it tries to renew the SSL certificate, which is why I asked whether it was somehow
caching an old DNS record - because maybe it is still thinking that the IP is the temporary one from the expired period, whereas the current/new IP should be the correct one pointing to our own server and ought to pass DCV with no problems.
2) Another domain may have a similar problem. It is partly hosted on a different server with a different hosting company. Some subdomains, including the mail server subdomains, are hosted on this server, but the main domain and the www subdomain are on another server.
In cPanel I
disabled AutoSSL renewal for the
main domain and the
www subdomain but
enabled AutoSSL renewal for the
mail subdomain. The IP address for the mail subdomain is that of our server. It is also getting the same AutoSSL renewal error message.
3) A third domain originally had no website. It was just used as a pointer to another site. The pointer was originally set using the domain registrar's control panel. A few days ago I changed the DNS settings so that the DNS and the website are now hosted on our server.
There is a 301 redirect in cPanel from this third domain to another site. There is also an A record for this third domain in our server's zone file, going to this server's IP address.
This third domain is also getting the same error message. I am wondering whether it is because AutoSSL is still seeing the old IP address set at the domain name registrar (which went nowhere), or if it is because the
pointer redirect causes problems with DCV.
Since it is just a pointer it is fine if it doesn't get an SSL cert, but we would at least like the mail subdomain to have a cert. There is no redirect for the mail subdomain and the A record for the mail subdomain is the correct IP address for our server.
4) AutoSSL was originally able to give SSL certificates to all three problem domains the first time around, so I am not sure why things have changed now.
I noticed that the change log in WHM mentions an update on 3/26: "Implemented case CPANEL-18952:
Update AutoSSL provider to sort vhost FQDNs for Apache TLS."
Could this change have had any effect on the renewals of the above 3 domains?
5) I temporarily disabled AutoSSL on the problem domain names yesterday. I was hoping maybe if I gave it a short break it would realize the IP had changed back to that of our own server after I re-enabled it.
However,
I just tested it again via the WHM UI as per your post, and it is
still giving the same error for all three domains.
Could you please clarify who you meant by "
license provider"? Is that a reference to the hosting company or the domain name registrar, or the certificate provider, or some other party?
If it's the hosting company I could try to ask them whether they manually disabled AutoSSL on those three domains. Could be they noticed the repeated errors and took action without letting us know.
Sorry for the lengthy reply (bolding added to hopefully make the key points stand out more from the wall of text

) and thanks very much for your help!