Isolated switch, fresh installs of Exchange 2016 (no whammies), new DC and new Win10 WS all in a virtual environment. They can all see one another fine.
Certificate Authority and DNS on DC and certificate issued to Exchange server. Other than one new user there are literally no other changes implemented.
No apparent issues with Exchange connectivity as ECP connection is fine. Can access Exchange using workstation and OWA with no issues. Test email to same user goes and comes back.
When flashing up Outlook 2016 it picks up user details but then chokes on "Logging on to the mail server".
Googled the heck out of it and tried everything and rebuilt fresh for a clean slate. Same issues.
It can't be much. Any fresh ideas?
