An Access-Request message was received from RADIUS client x.x.x.x with a Message-Authenticator attribute that is not valid

A client of mine recently had Enterprise Wireless (PEAP) wireless configured which connects to a NPS server to authenticate users connecting up.  People had issues connecting to the wireless after a new Domain Controller was brought online.

Checking the Event Logs, I found the following error:

This indicates that the Shared Secret between the Access Point and what's configured on the NPS (usually a DC) is not the same.  In order to get around this, I checked the settings of each Access Point and updated the Shared Secret.

Once you've done this, log into each access point and update the Shared Secret on to ensure that it's the same.  Once you've done this, the access points should communicate with the DC (or NPS) successfully.

Winthrop Australia provides IT Support in Perth.