It looks like a webgpu driver issue - can you tell me what model of graphics chip you're using?
FWIW I tried the other one linked here[1] which also throws the same error and stops. Using the same engine perhaps?
Yesterday when it didn't work I did try multiple times, and as mentioned that other site as well.
Guess Firefox on Windows has some flaky WebGPU support?
edit: must be, worked fine a couple of times, then it stopped with same error as before even after multiple attempts.