Controller failure does not have any impact on the traffic flow in the network. It is recommended not to create new instances in the protected group when there is a Controller failure. If a new instance is created when there is a Controller failure, it cannot be protected unless the Controller comes online.
In case of existing instances, they continue to redirect the traffic with the configurations before the Controller failure.
Use the following commands to debug the Controller further:
controller startcontroller stopcontroller statusshow log file controller.logshow editablesshow controllerVersionedit controller.json