Hi,
According to microsoft the default for NPS radius is 1500 and it may be fragmented in the router or firewall side that sits in between the nps and radius client.
I checked our radius clients and their default is 1500.
I already set NPS radius MTU to 1344 and still get the EAP error "Authentication failed due to an EAP session timeout; the EAP session with the access client was incomplete."
Should the MTU of the NPS Radius and radius client be the same?