Cannot load new program to my board

[COlva.1]

I am working with the BlueNRG-M2SA evaluation board and I am using the ST-Link / V2 to load program on the board,

I managed to load my first program on the board. But I can no longer load a new one.

When I load a new program onto the board, the old program is still running.

I reset the board, disconnect and reconnect it to the power supply but it did not fix the problem

If anyone has any suggestions to fix the problem, it will really helpfull.  

[Winfred LU]

Possibly your firmware application disables SWD pins or sets the device in sleep or standby state, in which SWD port is not powered.

To recover this situation, it is recommended to force DIO7/BOOT pin high and hardware reset the device in order to force execution of the bootloader. The user

can then connect with SWD interface and erase the device Flash memory.