Having an issue with clients registering their IPv6 to the AD DNS. They keep getting 8018 error events saying the DNS server rejected their request. I can't seem to narrow down the issue. All works fine internally and if I change the DNS server over to unsecured updates then it works fine. I would, of course, rather not do this.
If the clients can access the domain from the outside, browse network, run login scripts, get GP...why would the DNS server deny them? Any ideas on how to troubleshoot this? Thanks!
Server 2016 with Win10 1507 & 1809.