This is normal for third-party KKL cables. Use the "COM" selection, not "USB" in the software options. Firewall/Antivirus:
If successful, you will see a message saying "Interface: Found!" If you see "Interface: Not Found," double-check your COM port assignments in Device Manager and ensure the car's ignition is actually on. Troubleshooting Common Issues how to install vag kkl 4091 on windows 10