Hytale Server Error: “Server session token not available – cannot request auth grant”
Overview
When starting a Hytale server, you may see the following error in the server console:
Server session token not available - cannot request auth grant
When this occurs, the server will start but immediately reject player connections. This happens when the server has not yet been authenticated with a Hytale account.
This article explains why the error occurs and how to fix it using Hytale’s device authentication flow.
Symptoms
You may see one or more of these error 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 errors are present.
Cause
Hytale servers must authenticate against a valid Hytale account before they can create a server session token.
This error appears if:
- The server has never been authenticated, or
- The server was authenticated previously but credentials were not persisted and were lost on restart
Without a session token, the server cannot request an authentication grant and will refuse connections.
Game server providers like LOW.MS typically handle this authentication automatically. However, if you are running your own server instance, you will need to authenticate it manually.
Related Errors
Invalid Access Token
If you see "Invalid access token" or "Hytale invalid token" errors, this means:
- Your stored credentials have expired or become corrupted
- The authentication token is no longer valid
Fix: Re-authenticate the server using the steps below, then persist credentials again.
Authentication Failed
If Hytale server authentication failed, common causes include:
- Network issues – server cannot reach Hytale's authentication servers
- Hytale service outage – authentication services may be temporarily down
- Invalid Hytale account – the account used for authentication has issues
Fix: Check your network connection, wait and retry, or try a different Hytale account.
Session Expired
If you see "Hytale session expired" errors:
- Authentication tokens have a limited lifespan
- If credentials weren't persisted properly, they may expire on restart
Fix: Re-run /auth login device and ensure you run /auth persistence Encrypted afterward.
Solution: 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 — this is 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
- Open the verification URL: https://oauth.accounts.hytale.com/oauth2/device/verify
- Log in with your Hytale account
- Enter the displayed code if prompted
- Approve the authorisation request
Once completed, the server will authenticate automatically.
You should see logs similar to:
Authentication successful! Mode: OAUTH_DEVICE
Successfully created game session
At this point, the server is authenticated for the current runtime only.
Step 4: Persist Authentication with Hytale Auth Persistence (Required)
To ensure the authentication survives server restarts, you must enable Hytale auth persistence. Run:
/auth persistence Encrypted
You should see confirmation such as:
Credential storage changed to: Encrypted
Loaded encrypted credentials from auth.enc
This stores credentials securely and prevents the error from returning after a restart.
Verification
You can confirm the authentication state at any time with:
/auth status
An authenticated server will report an active session and credential store.
Want a Trouble-Free Setup?
If you would rather avoid manual authentication, command-line setup, and server management entirely, you can order a fully managed Hytale server from LOW.MS.
With LOW.MS:
- Server authentication is handled automatically
- Credentials are securely persisted for you
- Servers are preconfigured and ready to join
- No manual console commands are required
This is the simplest option if you want a reliable, low-maintenance Hytale server without dealing with setup issues or future authentication changes.
Summary
| Step | Action |
|---|---|
| 1 | Start the server |
| 2 | Run /auth login device |
| 3 | Authorise in browser |
| 4 | Run /auth persistence Encrypted |
| 5 | Restart safely |
Still Seeing the Error?
If the error persists:
- Confirm the Hytale account login completed successfully
- Ensure the server has outbound internet access
- Check that
auth.encexists and is writable - Restart the server after persisting credentials
Server Failed to Boot?
If your Hytale server failed to boot entirely (not just authentication errors), check:
- Java installation – ensure Java is installed and the correct version
- Memory allocation – verify the server has enough RAM allocated
- Port conflicts – check that the server port isn't already in use
- File permissions – ensure the server directory is readable/writable
These issues are separate from authentication and require different troubleshooting.
Players Still Can't Connect?
If the server is authenticated but players still fail to connect, see our Hytale Failed to Connect troubleshooting guide for connection-specific issues.
If you continue to have issues, contact LOW.MS support and include your full server startup logs.