ExplanationExplanationHow To Troubleshoot ISE Failed Authentications & AuthorizationsCheck the ISE Live LogsLogin to the primary ISE Policy Administration Node (PAN).Go to Operations > RADIUS > Live Logs(Optional) If the event is not present in the RADIUS Live Logs, go to Operations > Reports > Reports
>Endpoints and Users > RADIUS AuthenticationsCheck for Any Failed Authentication Attempts in the Log

Reference:
https://community.cisco.com/t5/security-documents/how-to-troubleshoot-ise-failed-authenticationsamp/ta-p/3630