Embedded ST-Link no more programming external boards

[MFail.11]

Hello

scenario: I have a Nucleo WB55 board with embedded ST-Link, and I'm able to program the mounted SMT32 with Cube programmer. I have used since few days ago the embedded ST-Link to program custom HWs, removing the jumpers on NRST, SWO, SWCLK, SWDIO, VDD MCU and GND and using cables to interface with the HW, and it worked. 

Since few day the ST-Link is not working more with external HW (no STM32 device detected) but is able to program the Nucleo itself ! So ST-Link works but not works ! It's pretty insane as behaviour. So what happened?

I changed cables, target HW, double checked connection with no luck.

With other Nucleos I'm stille able to program external HW in the same way, with this Nucleo no more.

[TDK]

Is the st-link detected in STM32CubeProgrammer?

Why can't you program other chips? What happens specifically when you try?

[MFail.11]

ST-Link is detected from Cube programmer, but when I click connect it shows an Error: no STM32 device detected (something like this), while the same device is detected perfectly with a different Nucleo.

And this nucleo with the problem worked since few days ago, now it can only program itself, but not other devices.

Is a mistery, any idea ?

[Tesla DeLorean]

There's only a handful of pins involved.

The Internal Target needs to be disconnected for the external one to be usable.

Check continuity for the SWDIO, SWCLK, GND, end-to-end. From far end to the pin on the ST-LINK IC, or disconnect jumper block.