OKAY. I solved the problem. I will write here so that other people know what to do. I had to upload new software to my SXCore- spacecraft-nx. Simple task so everyone should be able to handle it. There is a guide on how to do this on the Sthetix website.
A note from me. 1. If the flashing program freez on “Backing up the current bootloader” then you have a problem with the drivers.
2. After flashing, the chip will take a long time to boot. For me it took about 12 minutes. The LED will blinking green. Later, you should see a progress bar on the screen - red on a white background which looks like a glitch at first.