During the Rule(s) synchronization all of them are complied into one script and downloaded to the Zipato controller from Zipato Cloud Server. Because of this, if there is one invalid rule, java compiler will fail during the rule synchronization and a whole script will become invalid.
In that case rules should be examined for an error and the best way to debug is to disable last modified or created rule. If invalid rule is disabled and synchronization is repeated, script will pass Java compiler and rules will become operational.