So I'm just starting a server using Aternos, this is the first time I've ever run a server so I don't know the in and outs yet, however I do know basic minecraft things. Whenever I ran this server I made sure I was OPed, yet whenever I used basic commands such as; /kill /clear or even /help it said "An internal error occured while trying to perform this command." anybody know what this is and how I can fix it?