The shared system experienced some longer upload and computation times due to an unusually high load earlier today. Everything should be back to normal now, please try again and let me know if you still experience issues.
I could successfully upload your file using my personal account and a test Free account as well. Are you still experiencing it? Can you check if the browser console reports any error?
That’s the error message I get. I tried with another browser (edge instead of chrome) as well but am facing the same issue. Do you know what the problem could be?