Are you downloading the files on your local machine first and then copying them over into the server directory?
Ensure you are following these steps -
(start the server on your own PC first to download all the mods and configs)
Select correct forge settings
Hit the update button on the console to reinstall forge
Copy mods/config/defaultconfig/kubejs and other folders from local server install to the amp file manager
Hit Start on the console, does it prompt to access EULA and move on?