I just started your server successfully, it seems to work fine, I do not see any problems.
Aternos system is killing server that didn't get start for 30 seconds
We stop servers if they don't start in less than 5 minutes.
Learn more about this change here.
For help regarding Aternos, we recommend you to visit our support center.
I just started your server successfully, it seems to work fine, I do not see any problems.
Aternos system is killing server that didn't get start for 30 seconds
We stop servers if they don't start in less than 5 minutes.
We would never ban anyone for this.

Everything should work again by the way.
I just started and stopped your server with PermissionsEX, but couldn't reproduce the problem. Strange.
Can I have your Aternos username please?
Very poor translation though…

Please do not suggest plugins that already are available.

Denied, use LockettePro instead.

Added
It was probably just a temporary downtime. Try to access the page later again.
The team decides whether a plugins get added or not.

Denied
Please link the mod pack page, not the wiki page.

Make sure you server has finished its starting process and you connect to it using the correct Minecraft version and server IP address.
I was able to join your server, but it lags pretty much. Maybe you shouldn't spam so many commands using command blocks and should delete some worlds from your world Multiverse-Core configuration file.