Hello. I'm not sure if this really is an issue with Aternos or just the plugins itself but since it has happened to multiple ones here I am.
There are some plugins that come with a folder where you can add additional stuff for example the SkinsRestorer plugin where you can add your skin into that specific folder as a file. However, whenever I download these plugins they don't come with the folder making them pretty much useless. They only come with a document/jar. file and that's it. I've never had a problem with this before.
There might be something I am missing though.