Check the physical ethernet link lights on the ZKTeco device port. If the green and yellow lights aren't blinking, the cable or port may be defective.
You can run a targeted port scan on port 4370 across your network to pinpoint exact ZKTeco terminals: nmap -p 4370 --open 192.168.1.0/24 zkteco ip scanner
Once discovered, you can double-click a device or right-click to modify: Check the physical ethernet link lights on the