You downloaded fingerprints on the device (Download templates), and after that, the device reported duplicate fingerprints - the error message "Duplicate finger". The device gives such a message if the same fingerprint has been read in from several devices.
To resolve the issue:
First of all, delete the said fingerprint that the device displayed on the screen in the software "Terminals" - in the list "Fingerprints and Chips"
Perform "Download Templates" on the device again, i.e., and the device will delete the print deleted from the software also from the device
Next, go to the device with the employee who owned this fingerprint
In the device, select "Menu" - "User Management" - "View user ID" and check which fingerprint has already been entered into the device. If the device provides an ID number on the screen, this fingerprint is already present on the device and should not be added again.
Add one (or more) new fingerprints to the employee and link it to the correct employee in the software in the "Terminals" - "Fingerprints and Chips" option
Instructions for adding a fingerprint can be found HERE
In the future, if you want the employee's fingerprint to work on several devices, the employee's fingerprints must be read in from one device and manually linked to other devices. More on that HERE