It has been observed on numerous Proxy AV1400 models that they may Alert as Critical a whole host of Voltage (and other) Paremeters such as:
-3.3v Voltage
-12v voltage
-CPU Core Voltage
-Fan Speed
It is unlikely that all those components have failed at the same time, the more likely scenario is that the module that manages all those sensors has
stopped running (or lost communication with the sensors). If that is the case, a reboot should resolve this issue.