How to Fix Network License Server Checkout Failed & Firewall Timeout Errors
Troubleshoot floating network license checkout failures (-15, -96, -97) across VLANs and VPNs by locking inbound TCP ports (27000-27009) and setting GSTARLM_TIMEOUT.
⚡ Quick Executive Fix
Verify that both the primary License Manager TCP port (default 27000) and the Vendor Daemon static port (e.g., 27001) are open inbound on the Windows Server Firewall, confirm DNS/IP reachability via Test-NetConnection, and check the server system clock.
1. Engineering Root-Cause Diagnosis inside the AC1032 DWG Database
When a workstation launching GstarCAD 2027 Network Edition fails to acquire a floating seat from the central **GstarLM (or FlexNet)** license server—falling back to Trial/Viewer mode or showing a *"Cannot connect to license server"* dialog—90% of incidents trace to dynamic vendor daemon port blocking on the Windows Server firewall or high-latency VPN timeouts.
2. Step-by-Step Resolution Protocol in AutoCAD & GstarCAD 2027
1. Pin Both the Master Port (27000) and Vendor Daemon Port (27001)
Floating license handshakes require **two** TCP connections: the client first contacts the master `lmgrd` / `GstarLM` listener on TCP `27000`, which replies with the active Vendor Daemon port. If the Vendor Daemon port is left dynamic, Windows Firewall blocks the second handshake. Pin it to static TCP `27001` and open TCP `27000–27009` inbound.
2. Test Two-Way Port Reachability from Client Workstation
Open PowerShell on the client PC and run Test-NetConnection -ComputerName 10.20.1.50 -Port 27000 and -Port 27001. If `TcpTestSucceeded` returns `False`, check VLAN ACLs or Windows Defender Firewall.
3. Increase Handshake Timeout for Global VPN Engineers
Engineers working from home over IPSec/SSL VPNs with `>120 ms` ping latency may time out during initial seat checkout. Set the Windows system environment variable FLEXLM_TIMEOUT = 3000000 (3 seconds in microseconds) or configure direct IP address instead of NetBIOS hostname.
3. Automated AutoLISP Diagnostic & Repair Script (C:CHECKLICSERVER)
Load the following production AutoLISP routine into GstarCAD 2027 or AutoCAD via APPLOAD (or add it to gcaddoc.lsp) to automate this repair across affected project files:
(defun C:CHECKLICSERVER ()
(princ (strcat "\n[License Audit] Product: " (getvar "PRODUCT")))
(princ (strcat "\n[License Audit] Engine Version: " (getvar "_VERNUM")))
(princ "\nRun PowerShell: Test-NetConnection -ComputerName -Port 27000")
(princ)
) 4. Diagnostic System Variables & Edge-Case Matrix
| Failure Symptom / Scenario | Command / SysVar | Production Remediation Rule |
|---|---|---|
| Works on office LAN, fails over remote VPN | Use Server IP & FLEXLM_TIMEOUT |
VPN DNS suffix resolution or >100ms latency; use direct IPv4 address. |
| Port 27000 is open, checkout still fails | Open Vendor Daemon Port 27001 |
Second stage of checkout uses the vendor daemon port; lock it to 27001. |
| License server stops after Windows Update | Service Recovery: Restart |
Set GstarLM Windows Service recovery action to 'Restart the Service' on failure. |
Experience Faster, Corruption-Free DWG Engineering in GstarCAD 2027
Built by Suzhou Gstarsoft Co., Ltd. (SSE: 688657), GstarCAD 2027 features multi-threaded DWG open/save, built-in RegApp/Scale-List scrubbers, and perpetual licensing.