I've got a new user with a Surface Pro 4, she has Office 365 installed, which is currently up to date and running Office 2016. She had an email account setup in Outlook already, functioning fine. We created an active directory user and mailbox for her and she was able to log in just fine via webmail and change her password. The Surface Pro 4 is her personal device so we aren't requiring her to join it to the domain so at the moment it is just logging in with her personal account. If we try and use the default Windows 10 mail app, it is able to connect to exchange and retrieve her email with no problems. If we try and add a new account within Outlook 2016 it claims "cannot log into Exchange Activesync Server : server cannot be found". Things I have tried: 1. Creating a new Outlook Profile 2. Giving Outlook 2016 the server name every way I can think of. Example: exchange.mydomain.net exchange.mydomain.net/owa https://exchange.mydomain.net https://exchange.mydomain.net/owa 3. Ensuring Office 365 is updated.