I am almost sure that is a Windows Server issue.   https://support.microsoft.com/en-us/topic/the-nps-server-locks-a-user-account-after-four-tries-on-a-windows-server-2008-r2-based-computer-that-performs-authentication-for-radius-clients-4c5c5b82-ce96-0233-be7a-20985795aa84 ... View more