can´t flash Octopus V1.1 - Core-V4 500 IDEX

Hey,
I'm currently building a Core-V4 500 IDEX, the hardware is ready, but I'm failing to flash the Octopus 1.1.
I've already tried a few things, but every time I get the message “Octopus V1.1 detected but is unresponsive” (see picture)

The board has no jumpers and is powered by a 24V power supply. (see picture)
RatOS is up to date (see picture).

- I have tried to flash via DFU, for this I have set the boot jumpers once -> without success
- Automatic flashing -> without success
- Manually via SD card, I tried two different SD cards (4GB and 8GB), FAT32 formatted in 8kbit and 4kbit -> without success

Then I loaded a new bootloader (https://github.com/bigtreetech/BIGTREETECH-OCTOPUS-V1.0/blob/master/Firmware/DFU%20Update%20bootloader/bootloader/OctoPus-F446-bootloader-32KB.hex), the board establishes the connection with the PC without any problems. (see picture)
I then tried DFU, automatic and manual flashing again -> without success

What makes me very suspicious about my board is that the red LED does not flash, when I watch videos on Youtube the one LED always flashes.

Does anyone else have an idea where the problem could lie?

Regards
Chris