I am running a server using Apex Hosting and whenever I use the commands in the server it doesn't work. But, when I try it out in single player it does work. How do I get this mod to work in the server?

Have you installed the mod on the server? If you plan to use it on a multiplayer server then installing it on just your client isn't sufficient.

Yeah I'm pretty sure that it was installed on the server but I'll go check again