RDP Logins Not Always Asking for Duo 2FA

Hi,

We have Duo MFA configured for select domain accounts, configured to require Duo 2FA for local logins and RDP sessions on those accounts. From at least one domain computer to a remote computer (that has Duo installed) RDP login attempts are successful without asking for Duo 2FA (not what we would expect or want), but RDP logins from all other tested computers prompt for Duo 2FA. Any ideas why it could not be prompting for Duo from one of the computers on our domain, but it is prompting for the others? Duo is installed on the remote PC. Thanks for your time.

Enable debug logging, perform a login from that one RDP client computer, and review the debug log for more information.