"Not Found" after Upload

Hi,
I was looking for a service just like transfer.whalebone.io, but every time I upload a file, I can open the Link at most once before it leads to an empty page with "Not Found".

For example:
https://transfer.whalebone.io/yGhsI8wVy5/test.mp4

Did I run into some kind of rate limit due to fumbling around with my bash script for testing purposes?

Edit: It also happens when I upload the file manually via the web front end.