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"The item you requested does not exist on this server or cannot be served."

Seriously though, I was able to add a license to an audio file previously dl'ed from www.magnetmix.com, and later to remove the license.

I still am not clear what http address I would enter for my own files, and I expect to hear lots of confusion about that aspect.

re other problems:

with upload settings allowing 20 uploads per person and 20 uploads max, a 4.9.31 user got the "banned greedy client" treatment on the 5 th upload

That's a serious bug! I hope further work on the license branch should stop until other bugs, like the java.lang.OutOfMemoryError ones are fixed