Yeah, that’s not the whole story. I tried to tell briefly but I see it’s not enough :)
Let me tell from the beginning;
I upgraded macos high sierra to mojave (it’s not supported on my mac but there are some ways, anyway clearly it was not a good idea and didn’t have a good performance)
Then I decided to install high sierra (last supported macos) again. I made a bootable high sierra usb, format disk as apfs and started installation. Then at some point, it said ‘failed to install’. Then I opened diagnostics and I got this AHT error.
Now, I made my back up and want to install a macos that fits to my mac from the beginning. How can I get through this situation?