Home Assistant OS wont boot on Rpi4

Hey, I just tried to set up Home Assistant for the first time. I have a raspberry pi 4b and flashed Home Assistant OS onto an SD card but the pi wont boot, just stays on the red LED and doesnt give out any HDMI signal either.
The same SD card with something like raspberry pi OS works just fine, so that shouldnt be the issue. I have also tried formatting the SD card and installing Home Assistant OS again, but no changes.

Any Ideas?