Hi there 
I've been using Aternos for a while now and let me just start off by saying that you provide - for the most part - an incredible service!
Recently on the modded Project Ozone 2 modpack server that I started with some friends I have been having connection issues.
When in the multiplayer tab of minecraft it displays that I should have between 120-180ping on the server, however when I join my actions are delayed by minutes and I eventually get frustrated and leave. When I type in chat it takes a good few minutes for it to show on my end. This isn't an issue for my friend which is strange because I have 50mb up and 50mb down internet connection.
However it completely solves the issue when I change to my mobile data - which is definitely not the solution I'm looking for as I only have 1GB of data - starting to get quite frustrated haha.
Thank yo very much!