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User receives the error message "Invalid message authenticator in EAP request" in Access point.

Core Issue

The shared secret is not entered correctly in either the access point or the RADIUS server.


When you receive the Bad request from NAS error message and the Invalid message authenticator in EAP request failure code, then you need to check and re-enter the shared secret key in the access point and the RADIUS server.

A RADIUS server and the access point use a shared secret text string to encrypt passwords and exchange responses. In order to configure RADIUS to use the AAA security commands, you must specify the host running the RADIUS server daemon and a secret text (key) string that it shares with the access point.

For more information on how to configure the RADIUS server, refer to Configuring RADIUS and TACACS Servers.

Problem Type

Error message


Access point

Security Options






IOS Errors, Warnings, Statistics and Log Messages

Invalid message authenticator in EAP request

Version history
Revision #:
1 of 1
Last update:
‎06-22-2009 05:04 PM
Updated by: