Thank you very much !
You solved my problem perfectly.
Which kit are you using? By looking at your project, I guess you are using CY8CKIT-042-BLE.
Please make sure that the jumpers on the are at their default position before programming, by referring to the kit guide.
Currently I see that you are using the KitProg in CMSIS-DAP/Mass Storage mode. Try changing the KitProg to default programming mode and then try programming the device, see if that helps. Refer to section 4.1 Enter or Exit the Mass Storage Programmer Mode of KitProg User Guide for steps to change the KitProg mode.
The reason for this mistake is that I accidentally pressed the reset button for more than 5 seconds.
Thank you for your reply.