SDP is accessed via abc.xyz.com

Everything is working pretty well except, when a request is submitted via email, the requester account is created but login is not enabled.

Thus, the requester can't click on the hyperlinks in various emails (replies) until I go in and enable login for that requester.

Once I do, the requester can login in (their password being their email id).

So, how can I tell SDP to enable login for all (new) requesters from my domain xyz.com?