The most important thing is to make sure that the Server uses a Port that has access to the Internet.
This is done by ‘Port Forwarding’—please refer to your Router manual or ISP for details on how to do this.
The default port that the Server uses is 7777 (UDP), so be sure to forward it using the UDP protocol.
For additional troubleshooting tips, see what community members have shared on Discord: https://discord.com/channels/967763242514522212/1317621777005805668