Hytale Server Not Showing Up: Authentication, UDP and Version Fixes

A Hytale process can stay running while players still cannot join. The usual causes are different from older TCP game servers: missing server authentication, UDP-only QUIC networking, an exact protocol mismatch or a discovery listing that has stopped receiving heartbeats.

Use a managed Hytale server with provider authentication and tested UDP networking

1. Check authentication before networking

Run this in the server console:

/auth status

If the server says it is unauthenticated, it cannot validate joining players against Hytale services. For a personal server, start the device flow with /auth login device and complete the shown account link. If credentials have been offline for more than 30 days, the refresh token may have expired and a new login is required.

Hosting-provider setups should create a fresh game session before every process start. A one-hour session passed months ago is not a permanent startup secret, even though a continuously running process can refresh its session indefinitely.

2. Open UDP, not TCP

Hytale uses QUIC exclusively for the client connection. The default is UDP 5520:

sudo ufw status
sudo ufw allow 5520/udp
sudo ss -Hlun 'sport = :5520'

If the server uses a custom port, replace 5520 everywhere: the --bind argument, host firewall, cloud firewall and router forwarding rule. A TCP rule with the same number is not a substitute.

3. Verify the bind address and public path

Use --bind 0.0.0.0:5520 for a normal dedicated server. Binding only to 127.0.0.1 makes the process visible locally but unreachable from another machine.

If LAN connections work but public connections do not, the server process is probably fine. Check whether the router forwards UDP to the correct private address, whether two routers create double NAT, and whether the ISP uses CGNAT. A datacenter host avoids the home-router path but still needs its own provider firewall rule.

4. Match the exact Hytale version

Current Hytale builds compare a protocol hash during connection. The client and server must match exactly. If Hytale updated on a player's computer, check the server version and stage the current release:

/update status
/update check
/update download

Apply the update during a planned window or use the official WhenEmpty policy. Keep the Server directory, Assets.zip and launcher in the expected layout, because the update checker disables itself when that layout is missing.

5. Separate direct connection from Server Discovery

A direct address can work even when a community listing is absent. Hytale Server Discovery requires a server profile in the Hytale Account Manager, a verified domain, moderation approval and a discovery token configured on the server.

The listing is hidden when heartbeats stop for more than two minutes. Check the profile status and use the console command shown by the Account Manager to reconnect the discovery token. A hidden listing does not automatically mean the game port is down.

6. Test without newly added mods

Mods belong in Server/mods. A broken or incompatible .jar or .zip can stop startup before the server binds its QUIC port. Move only the newest additions out of the folder, restart and read the earliest exception in the log rather than the later cascade.

Keep DefaultModsEnabled aligned with what you intend to load. If the server starts cleanly without a mod, check its supported Hytale build before putting it back.

7. Protect config changes from the running process

Stop Hytale before editing Server/config.json, permissions.json, whitelist.json or world config. The server writes these files during operation and can replace a manual live edit.

Validate JSON after changing it. If startup broke after an edit, restore the previous copy rather than deleting the universe. Worlds and player data live separately under Server/universe.

A short diagnosis map

• Process runs but auth status is empty: complete device login or repair provider tokens.
• No UDP listener: inspect startup logs, Java 25 and mods.
• Local works, remote fails: fix UDP firewall, forwarding, double NAT or CGNAT.
• Version or protocol error: update the server files and Assets.zip together.
• Direct join works, listing is absent: inspect moderation, domain verification, discovery token and heartbeat.
• Failure began after a mod: remove that mod and confirm its supported build.

If you would rather skip the token and network work, a GHosting Hytale server starts through the official provider authentication flow, exposes the correct UDP port, tracks the official version, and includes a writable console plus file access. Nothing renews automatically.

Upstream details are in the official server manual, provider authentication guide and Server Discovery announcement.