What does ST-LINK/V2 saying "unknown target connected" mean?

[JBonn]

Unplugged JTAG from prototype unit for hand held testing. Need to plug back in for more code development . Using a STM32L476_LQFP64 chip. Did upgrade to STM32+STM8 Debugger from V2.J24.S37 to V2.J37.S37 and back. Neither version worked. Is there a "target list" that got deleted somehow?

[Tesla DeLorean]

No, your device is simply non-responsive.

And code in there to put the device into a low power mode, or interfere with the SWDIO/SWCLK pins?

Is NRST wired?

Try strapping BOOT0 High on your board, if that connects and you're able to erase, then something errant in your code.

[JBonn]

Tesla,
Thanks for your reply.
My device still runs (batteries) the last load put in it before unplugging for hand test. It drives an OLED display, buttons work, Etc. I can turn the unit on/off.
But, I cannot clear or access the chip anymore.
There are only five wires coming out of the ST-LINK V2 that are sent to the chip; (1) GND, (2) TCK_SWCLK, (3) TMS_SWDIO, (4) TDO_SWO, and (5) NRST.
If it is a wiring problem, one of these five must be broken.
If it is a code problem, I have not been able to identify it.
Any suggestions, especially code related?
Thank
Jerry