Open the CSiLicensing subfolder and run StandaloneKey.exe as an Administrator.
This solves 50% of Error 18 cases.
Understanding the "why" is crucial to preventing the error from recurring. The HostID of a computer is typically derived from hardware components like the MAC address (Media Access Control) of the network card, the hard disk volume serial number, or the motherboard UUID. etabs license error 18
Port 1947 must be open.
License Error 18: Security device not responding. Open the CSiLicensing subfolder and run StandaloneKey
If standard methods fail, corruption in the Windows registry may be the cause. the hard disk volume serial number