Command Blocks are not automatically enabled on your server and you have to turn them on.
Be careful, if someone changes their contents they may be able to get privileges on your server!
- Open the
Files
tab - Search for a file labeled
server.properties
and click it to edit - Search for
enable-commands-blocks
- It will be set to
false
by default, so change it totrue
- Restart your server. The command blocks will be enabled once done