Target not connected: NUCLEO-WB55RG

[PMana.1]

I am using  NUCLEO-WB55RG for developing a lorawan project targeted to  STM32WB55CG chip. I successfully downloaded the code using Keil IDE. When I was loading the code the windows machine was showing there is 3MB of space. I could run the code and debug. But when I tried to connect the Nucleo again I noticed that the disk size has reduced to 32KB. It has a fail.txt file in it and it says "The interface firmware FAILED to reset/halt the target MCU".

When I tried to load the code from Keil again it says target not connected and The flash download failed and Target DLL has been canceled. I connected it to cube programmer and was getting a target not connected message. I tried another new board and this problem happened again. My two Nucleo boards are useless and is it possible to factory reset the NUCLEO-WB55RG. Why did this happen? Is there anything wrong with the downloaded project? Please do help me to fix the problem. I am attaching the screenshots too. 

[Javier1]

You should change the topic to "STM32MCUs" instead of "STM32MPUs"

[PMana.1]

sure. thanks for the info.

[Javier1]

Its very weird the stlink is detecting 0.00V in the tarjet ....

• Did you removed any of the jumpers:

• Did you used cubeMX to generate the keil code?
• What version of cubeprogrammer and cubeMX are you using?
•  You could also try cubeprogrammer Mode=under reset

To flash the factory code again you would need to be able to connect to the MCU first...

[PMana.1]

I didn't use cubeMX to generate the code. It was a successfully compiled and tested code from a third party(SDK for lorawan). All the ides and applications were the latest versions. I could update the firmware too using the firmware upgrade option on cubemx. None of the jumpers are removed. Both boards are the same. Thanks