Hello,
Inventoria is your server program, its stock levels are updated as per the transactions you make on Copper. Copper can only be set to be the client of one program at the time, this means that if Copper is set to be client of the server program Inventoria, it cannot be set as the client for another server Copper program. Client Copper connected to Inventoria as server cannot communicate between them. To connect different Copper programs, one Copper must be set as server and other Copper installations will connect to it as clients, but they won't be able to connect as client of Inventoria too.