Troubleshooting SSH Errors on Thunder Compute

When you run ‘tnr connect’, Thunder Compute SSH’s you into your instance and manages keys automatically. Sometimes errors occur such as:

• ‘Bad permissions. Try removing permissions for user: \OWNER RIGHTS (S-1-3-4) on file C:\Users<your_username>.ssh\config.’
• ‘Error reading SSH protocol banner’ — this error may appear when your instance is low on memory, preventing a complete SSH handshake.
• ‘Key authentication failed’ — indicates that your SSH key may be outdated or misconfigured.

Follow these steps to resolve the issues:

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1. Restart Your Instance

Restarting can clear transient issues. In your terminal run:

tnr stop
tnr start

Wait about a minute before reconnecting.

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2. Test Manual SSH Connection

To get a more detailed error message, try connecting manually:

ssh tnr-0

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3. Fix Common Issues

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A. Out of Memory

If the instance crashes due to low memory—or you encounter errors like “Error reading SSH protocol banner”—wait and retry. For a permanent fix, create an instance with more resources:

tnr create --vcpus 8

Tip: Consider 16 or 32 vCPUs for increased memory.

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B. Permissions Issues

# Run PowerShell as administrator
icacls "$env:USERPROFILE\.ssh\config" /reset
icacls "$env:USERPROFILE\.ssh\config" /inheritance:r
Rename-Item -Path "$env:USERPROFILE\.ssh\config" -NewName 'config.old'

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C. Bad Configuration

Sometimes removing outdated config files helps.

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Known Hosts

Rename-Item -Path "$env:USERPROFILE\.ssh\known_hosts" -NewName 'known_hosts.old'

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Thunder Compute Locks & Keys

Remove-Item -Recurse -Force "$env:USERPROFILE\.thunder\locks"
Remove-Item -Recurse -Force "$env:USERPROFILE\.thunder\keys"

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4. Still Having Issues?

If problems persist, please reach out to us on Discord for further assistance.

Happy troubleshooting!