Hi Tim,
Yes, I have read in another thread that the expiration of the RADIUS certificate stops the Radius service.
The problem from the beggining was I was doing tests with authentication from only one IAP when the RADIUS certificate was valid. Then the next day I kept doing tests from the other IAP, but what a coincidence that the RADIUS certificate expired at the end of the previous day.
I will try to acquire new certificates and we'll see.
Regards,
Julián