Gearforge not drawing from other inventories

I installed a Gearforge on the Starter Platform connected to the grid using conveyor tubes and junctions. First, the conveyors didn't work to connect inventories when directly connected to ports. A conveyor junction has to be used between a non-conveyor port and a conveyor. For example, I connected the Assembler to a remote Cargo Container using connectors. The two inventory chains were not connected. (I also had a smelter and a number of 2.5m cargo containers where the Assembler is.) Instead, I had to replace the end points with Conveyor Junctions.

Next, I connected a Cargo Container to the junction, and then a Gearforge to the remote cargo container. Now all inventories are showing connected.

However, when I tried to upgrade my tools using the Gearforge, I had to go to the Smelter first to make the parts. Even then, the Gearforge didn't draw its needed materials from the Smelter. Instead, I had to drag them to my personal inventory and then to the Gearforge Input. I was using the Gearforge Input window to perform the dragging, so the conveyor system should have been fully connected.