Hytale Server Can't Connect: Fix UDP 5520 and QUIC Timeouts

If your Hytale server can't connect, or friends get "Failed to connect to server" or a connection timeout, the cause is almost always one of three things: UDP port 5520 is not open (Hytale uses QUIC over UDP, not TCP), the server and players are on different versions, or the server has not been authorised. Work through the quick fix below in order and most servers are joinable within ten minutes.

Quick fix

1. Check the server is authorised. Run /auth status in the console. If it is not logged in, run /auth login device and finish the browser step.
2. Open UDP, not TCP. Allow and forward UDP 5520 (or whatever port you set with --bind). A TCP rule on 5520 does nothing for Hytale.
3. Match versions. Update the game and the server so they are on exactly the same version.
4. Use Servers, not a share code. Friends should add your address under Servers > Add Server (or Direct Connect) as IP:5520.
5. Check the whitelist and password. If whitelist.json is on, only listed accounts can join.

The rest of this guide explains each step and the less common causes.

Why Hytale is different: QUIC over UDP

Most block games, Minecraft included, talk to players over TCP. Hytale uses QUIC, a modern protocol that runs over UDP, on port 5520 by default. That trips up a lot of people, because:

• Router guides and hosting habits often default to TCP.
• Some routers create a "TCP" rule unless you change the protocol dropdown.
• Windows Firewall may have allowed Java for TCP only, or only on private networks.

If you forwarded TCP 5520, the server looks fine in the console, but every connection from outside simply times out.

Step 1: Allow UDP 5520 through the firewall

On the machine running the server:

Windows (PowerShell as administrator):

New-NetFirewallRule -DisplayName "Hytale Server" -Direction Inbound -Protocol UDP -LocalPort 5520 -Action Allow

Ubuntu with ufw:

sudo ufw allow 5520/udp

Linux with iptables:

sudo iptables -A INPUT -p udp --dport 5520 -j ACCEPT

If you changed the port with --bind 0.0.0.0:5521 or similar, use that number instead. Also check any antivirus suite with its own firewall.

Step 2: Forward UDP 5520 on your router

1. Find the server's local IP address (ipconfig on Windows, ip addr on Linux), for example 192.168.1.50.
2. Open your router's admin page and find Port Forwarding (sometimes under NAT, Virtual Server or Gaming).
3. Add a rule: external port 5520, internal port 5520, protocol UDP, target 192.168.1.50.
4. Save, and give the server machine a fixed local IP so the rule keeps working after a reboot.

Our port forwarding guide covers the router side in more detail.

Test it properly. Test from outside your network, for example a friend's PC or your phone on mobile data with the game on another device. Joining with your own public IP from inside your home network can fail on routers without NAT loopback, even when everything is set up right. Players on the same network should use the local IP instead.

Step 3: Check for CGNAT

If the port is forwarded and it still times out, your internet provider may be using carrier grade NAT (CGNAT), where many customers share one public IP. Port forwarding cannot work through it.

To check: compare the WAN IP shown on your router's status page with what "what is my IP" shows in a browser. If they differ, or the router's WAN IP starts with 100.64 to 100.127, 10. or 192.168., you are probably behind CGNAT. Your options are asking your provider for a public IP, using a VPN style tunnel, or hosting somewhere else. Hypixel's server manual also notes that symmetric NAT setups can cause connection problems with QUIC.

This is where a hosted server helps most: it has its own public address, so there is nothing to forward and no CGNAT in the way. We are preparing Hytale server hosting, and you can join the waitlist to hear first when servers open.

Step 4: Fix a version mismatch

Hytale's client and server protocol versions must match exactly. After an update, players' launchers update automatically, and an old server refuses them.

• Update the server with the Hytale Downloader, or copy the new Server folder and Assets.zip from an updated game install.
• Compare the version on the game's title screen with the version in the server log.
• Plugins built for an older version can also break the handshake. If the versions match and joining still fails, move the mods folder aside and try again.

Chapter 1 lands on 12 October 2026, so expect every server to need an update that day.

Step 5: Check authentication

A server that has not been authorised starts up normally but refuses every player. Look in the console for:

No server tokens configured. Use /auth login to authenticate.

or

Server session token not available - cannot request auth grant

Run /auth login device, open the link, enter the code, then run /auth persistence Encrypted so the login survives restarts. The full walkthrough is in Hytale server authentication error.

Step 6: Whitelist, password and join method

• Whitelist: when the whitelist is on, anyone not listed in whitelist.json is refused. Add the exact Hytale account name, or turn it off to test.
• Password: if Password is set in config.json, players need it exactly, including capitals.
• Join method: a dedicated server is joined by address under Servers. The share codes used for friends' single player worlds are a different system.
• Address format: include the port if it is not 5520, for example 203.0.113.10:5521.

Stop the server before editing config.json or whitelist.json, or your changes may be overwritten.

Still stuck?

• Read the latest server log in the logs folder. The lines around a failed join usually name the reason.
• Check the server bound where you think: the startup log shows the address and port it listens on.
• Try a different network for the player. School, work and some public networks block UDP traffic that is not DNS or web.

Skip the port forwarding

Most Hytale connection problems come from running the server behind a home router. A hosted server has its own address and port, with nothing to forward and your home IP never shared. Our Hytale servers are coming soon: join the waitlist on the Hytale server hosting page, and see the Hytale quick start guide for what hosting will look like.

FAQ

What port does a Hytale server use?

UDP 5520 by default. You can change it with --bind 0.0.0.0:<port> on the launch command. It must be opened as UDP.

Does Hytale use TCP or UDP?

UDP. Hytale uses the QUIC protocol, which runs over UDP. Forwarding TCP will not let anyone join.

Why can I join my own server but my friends cannot?

You are connecting over your local network, which skips the router. Your friends come in through the internet, so the UDP forward, the firewall rule or CGNAT is the problem.

Why did my server stop working after an update?

The players' game updated and the server did not. Update the server files so the versions match exactly, and check your plugins support the new version.