AC not running, Honeywell HZ311 flashing “Cool”

My AC stopped working about 24 hours ago, and my Honeywell HZ311 zone board is flashing “cool.“ The back of the panel says this indicates a “low limit.“ I have tried resetting the breaker for the furnace and the error comes back. The fan has been blowing nothing but warm air for 24 hours, so I don’t believe this is a true low limit condition. Could this be a faulty DATS?