Reference: https://www.mist.com/documentation/wired-packet-capture/

Packet Capture: This feature allows for detailed inspection of traffic at the packet level. Capturing packets can help identify issues with authentication protocols, such as misconfigured settings or failures in the authentication exchange process.
Client Events: Monitoring client events provides insights into the client's authentication attempts, including successes and failures. This data helps in pinpointing where in the process the failure occurs, whether at the client, access point, or authentication server.
Reference:
Juniper Networks Documentation