To clarify by way of a different example:
Some video game publishers have released their game for free, anyone could download and play the game, but no longer provide it for free. Even if you downloaded the game while it was free, you cannot distribute it to others.
However, some publishers have made their games public domain, or another license that allows sharing. Once they have done that, they cannot take it back. You can share those games as much as you want even once the original site no longer provides it.
Check the license of any work you have downloaded that you want to share. Have they explicitly allowed you to share it as much as you want?