Add NX license Tailscale connectivity troubleshooting

- Document Tailscale connectivity issues between Windows and dalidou
- Add workaround to prioritize local IP (192.168.86.50) over Tailscale
- Include verification steps for testing both connection methods
- Document Windows Tailscale disconnection fixes (unattended mode)
- Fix hostname resolution issue where "dalidou" resolves to unreachable Tailscale IP

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/LICENSE-SERVER-INFO.md

@@ -188,10 +188,49 @@ ssh root@dalidou "tail -50 /opt/Siemens/LicenseServer/logs/lmgrd.log"
 ssh root@dalidou "systemctl restart siemens-lmgrd"
 ```
 
-### Can't connect from laptop
+### Can't connect from laptop - Tailscale connectivity issues
-1. Check Tailscale is connected: `tailscale status`
+
-2. Ping dalidou: `ping 100.80.199.40`
+**Problem:** Windows laptop can't reach dalidou via Tailscale (100.80.199.40), but local network (192.168.86.50) works fine.
-3. Check firewall: `ssh root@dalidou "ufw status"`
+
+**Quick Fix (if on same local network):**
+
+Update `SPLM_LICENSE_SERVER` environment variable to prioritize local IP:
+
+1. Open **PowerShell as Administrator**
+2. Run:
+   ```powershell
+   [System.Environment]::SetEnvironmentVariable('SPLM_LICENSE_SERVER', '28000@192.168.86.50;28000@100.80.199.40', 'Machine')
+   ```
+3. Restart NX
+
+Or via GUI:
+- `Win + R` → `sysdm.cpl`
+- **Advanced** → **Environment Variables**
+- Edit `SPLM_LICENSE_SERVER` to: `28000@192.168.86.50;28000@100.80.199.40`
+
+**Root Cause:** The hostname `dalidou` resolves to Tailscale IP via DNS, which may be unreachable if Tailscale connectivity is broken between devices.
+
+**Verification steps:**
+```powershell
+# Test local connection (should succeed)
+Test-NetConnection -ComputerName 192.168.86.50 -Port 28000
+
+# Test Tailscale connection (may fail)
+Test-NetConnection -ComputerName 100.80.199.40 -Port 28000
+
+# Check what dalidou resolves to
+Resolve-DnsName dalidou
+```
+
+### Tailscale disconnection issues on Windows
+
+If Tailscale keeps disconnecting on Windows:
+1. Run in PowerShell (Admin):
+   ```powershell
+   tailscale set --unattended
+   Restart-Service -Name "Tailscale"
+   ```
+2. Disable key expiry in Tailscale admin console: https://login.tailscale.com/admin/machines
 
 ### "All licenses in use" error
 Only 1 seat per license - close NX on other machines first.