Hytale Error - Server session token not available - cannot request auth grant

Overview

When starting a Hytale server, you may see this error in the server console:

Server session token not available - cannot request auth grant

When it happens, the server will start but immediately reject player connections. This means the server hasn't been authenticated against a Hytale account yet – it can't request a session token, and without a session token, no one can join.

This article covers why the error appears and how to fix it using Hytale's device authentication flow.

Symptoms

You may see one or more of these messages in your server console:

[HandshakeHandler] Server session token not available - cannot request auth grant
Server authentication unavailable - please try again later

[HytaleServer] No server tokens configured. Use /auth login to authenticate.

Failed to obtain authorization grant from session service

Invalid access token

Players will be unable to connect while any of these are present.

Cause

Hytale servers must authenticate against a valid Hytale account before they can create a server session token.

The error appears when:

• The server has never been authenticated, or
• The server was authenticated previously but credentials weren't persisted and were lost on restart.

Without a session token, the server can't request an authentication grant and will refuse connections.

Managed hosting providers like LOW.MS typically handle this authentication for you automatically at provisioning – which is why you'll almost never hit this on a hosted plan. If you're running your own server, you'll need to authenticate it manually the first time.

Related errors

Invalid access token

If you see "Invalid access token" or a similar error, your stored credentials have expired or become corrupted. Re-authenticate using the steps below and persist credentials again.

Authentication failed

If Hytale server authentication failed, the usual causes are:

• Network issues – the server can't reach Hytale's authentication servers.
• Hytale service outage – authentication services may be temporarily down.
• Invalid Hytale account – the account you're trying to use has a problem.

Check your network connection, wait and retry, or try a different Hytale account.

Session expired

Authentication tokens have a limited lifespan. If credentials weren't persisted properly, they may expire on restart.

Re-run /auth login device and then persist the credentials so they survive future restarts.

Fix: authenticate the server

Step 1: Start the server

Start your Hytale server as normal and wait for it to finish booting. The authentication error may already appear at this stage – that's expected.

Step 2: Run the device login command

In the server console, run:

/auth login device

The console will display a device authorisation prompt similar to:

Visit: https://oauth.accounts.hytale.com/oauth2/device/verify
Enter code: JuXnmQxD

Step 3: Authorise via browser

1. Open the verification URL shown in the console.
2. Log in with your Hytale account.
3. Enter the displayed code if prompted.
4. Approve the authorisation request.

Once that's done, the server completes authentication automatically. You should see something like:

Authentication successful! Mode: OAUTH_DEVICE
Successfully created game session

At this point the server is authenticated for the current runtime only – it'll lose the credentials the next time you stop it unless you persist them.

Step 4: Persist authentication so it survives restarts

Run the persistence command in the console:

/auth persistence Encrypted

You should see confirmation along the lines of:

Credential storage changed to: Encrypted
Loaded encrypted credentials from auth.enc

This stores credentials securely in a local file (auth.enc) and prevents the error from coming back every time you restart.

If your build doesn't recognise persistence as a subcommand of /auth, run /auth --help to see the exact subcommand it uses – the auth command set is still evolving in Early Access.

Verify it's working

You can confirm the current authentication state with:

/auth status

An authenticated server will report an active session and a configured credential store.

Summary

Still seeing the error?

If the error persists after all of the above:

• Confirm the browser login actually completed successfully.
• Ensure the server has outbound internet access.
• Check that auth.enc exists in the server directory and is writable.
• Restart the server after persisting credentials and confirm the error doesn't come back.

Server failed to boot entirely?

If your Hytale server failed to boot (not just authentication errors), check:

• Java installation – Java 25 must be installed and on the path.
• Memory allocation – verify the server has enough RAM allocated.
• Port conflicts – check that UDP 5520 (or your custom port) isn't already in use.
• File permissions – the server directory must be readable/writable.

These are separate from the authentication flow and need different troubleshooting.

Players still can't connect?

If the server is authenticated but players still fail to connect, the failed-to-connect troubleshooting guide covers connection-specific issues – firewall, port forwarding, whitelist, version mismatch.

If you're on LOW.MS and stuck, open a support ticket from the panel with your full server startup logs attached and we'll take a look.