License Error 18 in ETABS (or any CSI software like SAP2000 and SAFE) typically means "The server is down or not responding." Essentially, your computer knows where the license should be (the Server Name/IP is correct), but it cannot communicate with the server computer to actually borrow the license. Here is a step-by-step guide to troubleshooting and fixing this error for the 2021 version.
Phase 1: The "Have You Tried Turning It Off and On Again?" Before digging into settings, try these quick fixes:
Restart the License Manager Service:
Go to the computer acting as the License Server. Open CSI License Manager (or Sentinel RMSSetup). Stop the service, wait 5 seconds, and Start it again. Try opening ETABS on the client machine again. etabs license error 18 2021
Check the Client Count:
Open the CSI License Manager on the server. Check if you have already used all available "Seats." If you have 5 licenses and 5 people are using them, the 6th person will get an error (sometimes Error 18 if the server is overloaded).
Phase 2: Network Connectivity (Most Common Cause) If the server is running but ETABS still gives Error 18, the issue is usually a blocked connection. 1. Ping the Server: License Error 18 in ETABS (or any CSI
On the computer getting the error (Client), open Command Prompt (cmd). Type ping [ServerIPAddress] (e.g., ping 192.168.1.50 ). If Request Timed Out: Your computers are not talking. This is an IT/Network issue (firewall, wrong subnet, VPN issues, or bad Wi-Fi).
2. Disable Firewalls Temporarily:
On the Server: Temporarily turn off Windows Defender Firewall. Open CSI License Manager (or Sentinel RMSSetup)
Go to Control Panel > System and Security > Windows Defender Firewall > Turn Windows Defender Firewall on or off.
On the Client: Do the same. Try opening ETABS. If it works, the Firewall is blocking the license port. You need to create an Inbound/Outbound rule to allow the CSI License Manager application.