Failed to execute MI command

[DavidL_]

I recently started getting the following error when trying to program my nucleo-32 L432KC board:

Error in final launch sequence:

Failed to execute MI command:
target remote localhost:61234

Error message from debugger back end:
localhost:61234: Connection timed out.
Failed to execute MI command:
target remote localhost:61234

Error message from debugger back end:
localhost:61234: Connection timed out.
localhost:61234: Connection timed out.

I have tried using the cube programmer to erase the flash memory, but when trying to connect with "Mode: Normal", I get an error: "Error: ST-LINK error (DEV_TARGET_HELD_UNDER_RESET)". When changing the Mode to "Hot plug", I am able to connect to my MCU, but the "Full chip erase" operation gives me the error: "Error: Mass erase operation failed.Please verify flash protection".

Does someone have an idea what could cause this? Programming the MCU worked just fine a day ago.

[DavidL_ · Accepted solution]

Ok this was solved by breaking the S9 solder bridge.

[Andrew Neil]

Details here:

https://community.st.com/t5/stm32-mcus-boards-and-hardware/program-not-running-when-powering-from-external-source/td-p/723553