Set up an SRV Record
If you have a dedicated IP, you can skip this step - You are done. Otherwise, you'll need to set up an SRV Record with the following properties:
Name: play (If you put in a different value in step 2, you must also change it here)
(The subdomain you want players to connect with)
Port: 12345 (Change me to your port)
TTL: 30 min.
After setting up an SRV record, you may need to wait up to 30 minutes before it works.