2.6. FQDNs For Replication

OpenDJ replication requires that you use fully qualified domain names, such as opendj.example.com.

Although you can use host names like my-laptop.local for evaluation, in production and even in your lab, you must either ensure DNS is set up correctly to provide fully qualified domain names, or set up /etc/hosts (or C:\Windows\System32\drivers\etc\hosts) to provide fully qualified domain names.