Please attempt the following steps to troubleshoot your device.
In each of this steps, insert the YubiKey into the USB Port, open a text editor (such as Notepad) and press the button on the YubiKey.
1. Use the YubiKey in a different USB Port on the same computer.
2. Use the YubiKey in a different computer.
Please then write to us with the following.
1. The output you see on the text editor.
2. The behaviour of the green LED both when you insert the YubiKey and when you touch the button.
3. The operating systems that were running on your computers.
Posted in: 2. The YubiKey