RADIUS 802.1x broken after MR Firmware Upgrade

[TMS]

RADIUS SSID setup via Windows NPS Server machine certificate authentication. Working perfectly on firmware version 29.5.1. Upgraded MR Firmware to 30.7 and none of the clients on the SSID configured for RADIUS access will connect. Rolled back upgrade, works again.

Windows NPS Server event logs show no problems, successfully authenticating all requests. No error logs seen on the Meraki dashboard event logs. Client computers just say 'Can't connect to this network'

Lost since I can't find actual error codes on Meraki Dashboard or on the NPS server. Posting here in case someone else sees or has seen this and can provide guidance, I will also open a ticket with support and update this post accordingly.

[KarstenI]

I am running 30.7 and 802.1X is working as before. Can you post what you see on the Dashboard-Log? But I would also open a support case to let Meraki look at the problem while you try to authenticate.

[PhilipDAth]

If these are Windows clients - anything in the event log around the failure times?

[redsector]

ISE says: "The Message-Authenticator RADIUS attribute is invalid". Altough it is correct.

[pjc]

another thread about this here

https://community.meraki.com/t5/Wireless/30-7-Update-Breaks-RADIUS/m-p/241979#M33274