STM32CUBEIDE Error

[Ktaew.2]

Hello, in my current project, MCU is using STM32F446ZET6 and emulator is using ST-LINK/V2-ISOL. I am trying to connect with JTAG, but when I debug with CUBEIDE, Target no device found appears. I checked the Vcc (1pin) of the connector, but before connecting the emulator, 3.3v is normally coming out, but when I just connect it, 0.4v comes out and it doesn't work properly. What should I do in this case?

[TDK]

Emulator? You mean debugger?

The board needs to be powered. Pin 1 is a voltage detection pin, not intended to power the device.

Is this a custom board? How is it being powered?

[Ktaew.2]

Yes emulator stands for jtag.

I am attaching my schematic.