Pretty simple one this one… If when trying to join a domain name, and its coming back unable to join with error code 1355 (which generally means it cant talk to the domain controller via DNS) – Ensure that your IPv6 DHCP is serving IP addresses or disable the protocol in network connections.
As I’m not running IPv6 on my personal domain, Windows Server 2019 had a hard time trying to via it (IPv6 takes preference over IPv4 by the looks of it!)