Activate command blocks at Aternos?

Me and my girlfriend play together in an Aternos Minecraft server. Now let's do something with command blocks. In the chat is only when we have entered the command in the block,

Command blocks are not activated on this server.

But now I've watched a video on YT where I have to write into the console:

enable-command-block-true

It still does not work.

Can anyone help me?

Have you activated command blocks in the server settings?

It is best to stop the server once, activate the command blocks and then restart the server

Okay, I'll try it out.