Can’t break or build blocks?

So, the title says it. However I can build or break when about 15 squares away from my base (I am in a server). Server has been restarted, to no avail. Various other things have been tried. Any thoughts?

There is a protected area around a server spawn, to prevent players griefing the place where everyone spawns in. Move away from that area, or ask the server owner to change the protection radius (requires editing and a restart).

Normally all Minecraft servers will have this enabled by default.