I had created a new domain, with new DNS entries, however, because I did a dig request locally to just before the DNS had propagated, it refused to return valid values despite the DNS records TTL having expired. I found out that this was because AdGuardHome has a local DNS cache, however, this meant that my DNS refused to resolve. I couldn't find any documentation on this either besides the config values, so I ended up taking a stab in the dark and restarted AdGuard Home as I'd figured the cache must be in memory.
Quick update: cache will be cleared if you disable and then enable protection.
This may be implemented alongside #1685
Quick update: cache will be cleared if you disable and then enable protection.
Odd, I did try that, but the record still wouldn't resolve. If it happens again, I'll definitely double check and perhaps raise a bug issue.