Only one port will read at a time

I have two flow sensors connected to my kegboard and I can only get one to read at a time when it’s the sole one plugged into the board. Any ideas? I have a Kegbot server setup on Digital Ocean that has been working fine with one tap for weeks. Now that I have two beers ready, I would obviously like to get it working for both taps.

How are the flow meters how are the wires mapped? There is a chart on this page that shows where to map them to