| Symptom | Cause | Fix |
|---|---|---|
tailscale up auth fails | Network issues | Check internet, try curl -I login.tailscale.com |
| SSH connection refused | SSH not running | Run sudo systemctl start ssh --no-pager on Spark |
| SSH auth failure | Wrong SSH keys | Check public key in ~/.ssh/authorized_keys |
| Cannot ping hostname | DNS issues | Use IP from tailscale status instead |
| Devices missing | Different accounts | Use same identity provider for all devices |
For latest known issues, please review the DGX Spark User Guide.