In simplest terms, the following events will take place if a health check fails and failover occurs:
Route 53 conducts a health check of your application. In this example, your application fails three consecutive health checks, triggering the following events.
Route 53 disables the resource records for the failed endpoint and no longer serves these records. This is the failover step, which causes traffic to begin being routed to your healthy endpoint(s) instead of your failed endpoint.