When we try to add external users on the management part of the portal, we have 3 cases :
users company has no Bentley account : no problem (completing info and adding user to list)
user has an account but no PW licence : option to add to account (immediately after entering e-mail address, see 1.jpg)
user is within an IMS Federated with AD company : "could not create user" (after having to fill all the information fields see 2.jpeg)
This last error showing doesn't indicate anything to the admin... it could be better to have a modicum of information on th "why"...