I've been having issues getting farms and machines to work AT ALL on my Aternos server. It's free and the lag is bearable for a couple users. The problem is that none of my machines work.
You can see here that I can get the hopper to stick, and it looks like it might work, but the stacked items will disappear as soon as you interact with them.
I tried making the same machine on a different local world and it worked properly.