: If a "COM Key" is set on the device, the same key must be entered into the software settings. A mismatch here will result in an immediate connection failure. 3. Software and Firmware Fixes
: ZKTeco devices often use default ports like 4370 (TCP) for proprietary protocols, 3718 for SSH, or 23 for Telnet. Ensure these are not blocked by a firewall. zkteco authentication failure solution best
In some cases, the error is triggered by license verification or corrupted system files. How to Fix ZKTeco Authentication Error on Biometric Devices : If a "COM Key" is set on