3 zones across 2 controllers suddenly stopped working

I have 2 Gen2 16 zone controllers that are operating 24 total zones. I previously was using a single 24 zone controller to control all my zones but migrated to the rachio platform with Gen1 over a year ago. I upgraded to gen2 and have been loving everything! Today I noticed 3 separate zones will no longer come on spread across both controllers. I can confirm they were working about a month ago when I reinstalled the system with Gen2 controllers. I’m not sure if it matters but I have 4 common wires feeding the 2 controllers but cannot guarantee each common coincides with appropriate zones for each controller as I separated out the grass and flower zones. Is there anyway to test what may be causing 3 zones not to operate?

It sounds like one of your common wires broke. I would test each zone at the clock (voltage meter from the common to the zone number), then at the valves.