Hello Community,
here is a list of FAQ's so that u dont have to ask every single time. Original posted by Goldzora FAQ translated by Dixiklo.
FAQ
Q: My server is not starting...
A: Please go to our homepage aternos.org and check out if our servers are not overused at the moment. If they are used about 90% just wait some minutes and try agein 
Q: Starting my server takes to long...
A: Please control the start of your server with the console application which is given on the server-webinterface and look for errors with used mods. U might also check our homepage for overused servercapacity.
Q: My server is lagging...
A: Again please check first our homepage for usage of servercapacities. If the servers are not overused it can help to restart the server. If your server is still lagging u might delete some mods or contact us on our forum 
Q: I did not receive my activation email...
A: Please look in all of your email categories the email might be in the spam category. If it is not in there u can contact us at our Teamspeak-Server: ts.aternos.org
Q: I cant upload my own world...
A: Please check if you activated JavaScript and Cookies. U might try another webbrowser and please remember that your world has to be packed in a .zip-file which size is not bigger than 50mB.
Q: What do u mean by 'Webinterface' ?
A: Your webinterface is the place u can configure your server by clicking on your name in the left upper corner and then on "myserver".
Q: I have a question about a plugin...
A: Please check out the bukkit plugin page first. The link to the page is given at the plugin list.
Q: How do i delete a modpack ?
A: The best way to delete a mod is to reset the whole server so u do not get difficulties with any mod that is not deleted right. DONT FORGET TO DOWNLOAD YOUR MAP BEFORE U RESET THE SERVER !!!
I hope my translation was clear enough 
Sry for some mistakes but i am german aswell as the most part of this forum and my english is sometimes pretty sh** :DD 