Garry's Mod Addon doesn't load

I have created an Addon which works fine on my local server, but It isn’t showing the item in the detectiveshop on the “real” server and the “give” command also doesn’t work.
I also don’t get any error messages.

gma addon or a folder based addon?

folder-based
only these three files:
<addon folder>/armor/lua/weapons/armor.lua
<addon folder>/armor/materials/vgui/ttt/armor.vtf (and vmt)

So it’s garrysmod/addons/armor/lua/weapon/armor.lua ect?

When the server starts up do you see "Adding Filesystem Addon ‘%installdir%/GarrysModDS/garrysmod/addons/armor’ ?