Connect Hytale server can't connect? Check these 6 things in this order

Hi Hytaler,

short answer: Hytale uses UDP port 5520, not TCP. Most "can't connect" problems are a TCP port forward, a closed firewall, or client and server on different versions after an update. Go through the list below in this order, it takes 5 minutes and saves you a reinstall.

Don't want to read? Our connection checker asks you a few yes/no questions and tells you the likely cause.

1. Is the server really running?​

Sounds stupid, but check it first. On Linux:

sudo ss -ulnp | grep 5520

Nothing there = no server listening, the network is not your problem. Look in the log, usually it says it straight: wrong Java, missing --assets Assets.zip or auth not done.

2. Same version on client and server?​

After every Hytale update this is number one. Your launcher updates the game, the server is still on the old build, nobody gets in. Update the server, restart, done.

3. UDP, not TCP​

The server only listens on UDP 5520 (QUIC). A TCP forward does nothing.

Firewall on the server:

sudo ufw allow 5520/udp

On Windows: allow Java / the server in the Windows Firewall for private and public network.

Router: forward UDP 5520 to the local IP of the server. Some routers save only TCP if you pick "both", check it again after saving.

4. CGNAT (hosting from home)​

Many internet connections (most mobile, a lot of fibre) don't give you a real public IP. Then no port forward will ever work.

Check: compare the WAN IP in your router with what a "what is my IP" site shows. Different? You are behind CGNAT. Options: ask your ISP for a public IPv4, use a tunnel, or get a small VPS.

5. Testing from your own network​

You can't test your public IP from inside your own LAN, most routers don't loop it back. People at home use the local IP, friends use the public IP. To test from outside, use your phone on mobile data.

6. Java 25 and auth​

• java -version must show 25. With Java 21 the server crashes on start before it opens the port.
• New machine, restored backup or token gone? Run auth login device in the server console again. Without auth nobody can join.

Quick checklist​

sudo ss -ulnp | grep 5520      # listening?
sudo ufw status | grep 5520    # firewall open (udp)?
java -version                  # 25?

Still not working? Open a thread in Server Setup & Hosting and post your server log (last 30 lines), not only "it doesn't work"

New server? The full setup is in the server setup guide, RAM sizing is here.

• BitaceS

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