We have DUO Authentication working for RRAS (SSTP) on Server 2019 by use of the pre windows 2000 logins. We would like to have it to work with the userprincipalname. For that we have a directory sync in the portal that uses this and that part seems ok.
In the authproxy cfg we have a line under [ad client] that also states to pick the userprincipalname.
Yet, when using a windows 10 desktop to connect to the vpn, only logging in with samaccountname works (wich is setup under directory sync as alias 1).
Some advice would be welcome.