Hello, Aternos Team 
Can you add the following plugin please
Name: PermissionsEx
Link: https://dev.bukkit.org/projects/PermissionsEX
Description:
PermissionsEX-this plugin makes it easy to differentiate the rights of players on your server. It is the most popular permission management tool at the moment.The plugin can be downloaded here (the Latest version).The package contains three plugins:
ChatManager-chat Manager (Prefixes, color).
Modifyworld-modification of the world (Alternative: EssentialsAntiBuild).
and, in fact, the "PermissionsEx.jar".
Put " PermissionsEx.jar "to the" plugins " folder of your server. Start the server. Wait for 2 minutes (to create plugin settings) and install.
Look in the "plugins" folder. A new "PermissionsEx" folder should be created.
There are two files inside the folder:
config.yml - configuration of the plugin.
permissions.yml is the actual list of permissions.
If you add this plugin! Thank you!