Hello and thank yhou for your reply.
The large box is model QIP7100-P2. The smaller one is DCT700. After inital setup, the large box was working on the TV on the first floor. The smaller box was left connected to the source upstairs as I did not have a TV yet. When I got a new TV, I decided that it'd be better to have the TV upstairs be the primary and swapped the boxes. The large box works fine. I do not have a splitter on the smaller box as the router is upstairs with the larger one. Later this evening I'll try moving the boxes to see if the smaller one works upstairs with the router and splitter.