4 out 5 zones stopped working

Hi. I have a Gen 2 with 5 zones. Just realized that 4 out of my 5 zones are not working. Any ideas on what could be wrong. I’ve had the system for about a year and everything has been working fine. When I run the bad zones nothing happens. My valve boxes are above ground and easy to get to. If it was jut 1 then I would think it was a solenoid but I think it might be something more. Thanks!