Can you send the logs after trying to start it? They can be found on your dashboard > file manager > logs > latest.log. Send them in a pastebin or hastebin.
Hey, try oping yourself through the console and then run /worlds. To op yourself, go to your dashboard > appearance > server command and type /op <your username>. Then, press send and you should be able to run /worlds.
Make sure you have the * permission (gives you all permissions in the game) if you have a permissions plugin installed and then try it. If you want to find the exact permission for it to give your players permission, then I'd recommend checking the plugin website.