This simple use case can be solved with standard Mendix functionality, so you don't need to override the login actions. I have explained the general principle here (use a before commit microflow on account), you can easily adapt this to set the Active boolean to false once the FailedLogins attribute >= 3.
Nolan,
Did a bit of searching - there is a good article here by Bart Groot about how you can accomplish. Not sure if the code in the post is compatible with 5.13.1, but its at least a starting point.
Mike