How to Change your Server Slots
1) Login to your Panel Account at https://gamecp.cubes.host and click your server's name
2) Stop your server
3) Go to your file manager and locate the server.properties
4) Edit the server.properties file and find the max-players attribute, by default you'll see 20
5) Change 20 to the maximum amount you would like for your server slot
6) Save the file
7) Start up your server