Using the event logs in Event Viewer, you can monitor Network Policy Server (NPS) errors and other events that you configure NPS to record.
NPS records connection request failure events in the System and Security event logs by default. Connection request failure events consist of requests that are rejected or discarded by NPS. Other NPS authentication events are recorded in the Event Viewer system log on the basis of the settings that you specify in the NPS snap-in. Some events that might contain sensitive data are recorded in the Event Viewer security log.