Grove - Capacitive Fingerprint Scanner/Sensor code is not working

I have just purchased one grove capacitive fingerprint sensor. link.

I am using Arduino Nano and followed their tutorial but the example code isn’t working. A blue light on the sensor never turns green as it should according to the code. Also, it says register ok without putting any finger on it.

I am sharing the result of the full process code.

Wait for respono indicates that an error occurred.



Uart===> : EF.1.FF.FF.FF.FF.1.0.8.31.0.1.4.0.7.0.46. 

Usage:
Please put your finger on the touchpad, from green light which on the touchpad lights on till it lights off.
Repeat for 4 times.
If the red light lights on, it indicates that an error occurred.

Wait for response of finger-print sensor 5 seconds
Wait for response of finger-print sensor 10 seconds
Wait for response of finger-print sensor 15 seconds
Wait for response of finger-print sensor 20 seconds
Wait for response of finger-print sensor 25 seconds
Wait for response of finger-print sensor 30 seconds
Wait for response of finger-print sensor 35 seconds
Wait for response of finger-print sensor 40 seconds
Wait for response of finger-print sensor 45 seconds
Wait for response of finger-print sensor 50 seconds
Wait for response of finger-print sensor 55 seconds
Wait for response of finger-print sensor 60 seconds
Wait for response of finger-print sensor 65 seconds
Wait for response of finger-print sensor 70 seconds
Wait for response of finger-print sensor 75 seconds
Wait for response of finger-print sensor 80 seconds

thanks in advance

Hello, I have tried grove Arduino Sheild and download Seeed_Arduino_KCT202 library from the GitHub link provided in Seed official website.

Then I installed the library and opened File → Examples → Seeed_Arduino_KCT202 → full_process.

And after this output is

Uart===> : EF.1.FF.FF.FF.FF.1.0.8.31.0.1.4.0.F.0.4E. 

Usage:
Please put your finger on the touchpad, from green light which on the touchpad lights on till it lights off.
Repeat for 4 times.
If the red light lights on, it indicates that an error occurred.

Uart<=== : EF.1.FF.FF.FF.FF.7.0.5.0.0.0.0.C.

Register ok!
EF.1.FF.FF.FF.FF.1.0.8.32.0.FF.FF.0.7.2.40.
Uart===> : EF.1.FF.FF.FF.FF.1.0.8.32.0.FF.FF.0.7.2.40.

Please put your finger on the touchpad, from green light which on the touchpad lights on till it lights off.
To verify your finger print.

Uart<=== : EF.1.FF.FF.FF.FF.7.0.8.0.0.0.0.0.0.0.F.

Verify ok!
Your finger temp id = 0
EF.1.FF.FF.FF.FF.1.0.3.D.0.11.
Uart===> : EF.1.FF.FF.FF.FF.1.0.3.D.0.11.

Uart<=== : EF.1.FF.FF.FF.FF.7.0.3.0.0.A.

Operation succed.
Delete ok!

I haven’t touched the sensor but it registers by its own.

Please help.

Thanks in advance.