
You should be able to modify the range in the Citizens configuration files.
Learn more about this change here.
For help regarding Aternos, we recommend you to visit our support center.

You should be able to modify the range in the Citizens configuration files.

Outdated or already added.
I only added ShopChest and Itemizer, the other plugins either cost money or are outdated.

I recommend you to watch some tutorial then on how to use these plugins correctly.
You probably mean the newer Essentials versions: https://hub.spigotmc.org/jenkins/job/spigot-essentials/
Unfortunately, we can't add them to Aternos as they're not available at DevBukkit or SpigotMC.
It's only possible to install mod packs which are available on our site though, it is not possible to upload your own mod packs. More mod packs to be added to our site can be suggested in these forums.
You can edit your plugin configuration files at the Files & Plugins page.
Unfortunately, it's not possible to download worlds that had been created with Multiverse-Core or Multiworld. You can only download your main world at the moment.
We're no plugin creators, we just run Aternos. If you find a plugin with such functionality you may suggest it in these forums.
Gegebenenfalls musst du vorher erst eine PermissionsEX-Konfiguration erstellen, damit du das Plugin richtig benutzen kannst.
What exactly do you mean? What are 'snapshot plugins'?
What error message exactly does he get when trying to join his server?
Must be the world then since you said a new world worked fine.
This might be because of this help.aternos.org/en/countdown but I do not really have that much experience with Aternos.
That article is outdated and doesn't apply to the current system anymore.
Check the server console log for more detailed error information on why your server stopped. Most likely it just crashed.

Added
Maybe your world prevents the server from starting and you would need to start a new one for the server to work.


You would need a real static IP address for the plugin to work.