Radius request to Active Directory Domain Controller running Network Policy Server suddenly stopped working

[Mattias_Anderss]

We have a V2110 Controller set up to do authentication with RADIUS to our AD server using MSCHAP v2. But it suddenly stopped working.
In the log on the AD server I can see this many times in application log:
Negotiation failed. No available eap methods.
It never appeared before it was working and now it's showing that error a few times every minute.
I tried duplicating the Network Policy, disabling the old one and renaming the new one to the old ones name. But no luck.
Anyone else bump in to this?

[Mattias_Anderss]

Thanks Doug, got that fixed, the server the CA server the DC was pointing to had been turned off. Installed one locally on that DC, so I no longer get that error. I configured the NPS to match the config in your screenshots.
The clients are now prompted to accept a new certificate, which makes sense.
But now instead I get "Connection failed." when trying to connect from a Mac.
If I log on to the controller and do a test of the radius, it returns Test Completed, but with ACCESS_REJECTED. I'm guessing that is expected as it never asks for a password and I'm assuming it's just testing the actual radius connection?

[Doug]

Like Ron stated you would want to review the NPS Event log to see why the client failed to connect. There is usually a reason code.

Here is an example:

[Ronald_Dvorak]

There is only one place where I look in such case... the NPS log.
The controller is only the message forwarder between the wireless client and the NPS and has no clue what this 2 talk to each other.

[Mattias_Anderss]

Thanks. Any other ways to test what is going wrong in the auth that you can think of?
I ran wireshark on the radius server and I can see the connections coming in. But for some reason it just gets connection failed on the client side.