Outlook 2016 doesn’t use OWA to connect outside the office like 2013 did – it relies solely on the published cert. If you don’t have one, or it’s just being a dick, you can do this. Specifically, the XML/reg thing.
Also, ran into this nonsense where I couldn’t add or remove profiles in Control Panel>Mail deal with 2013. Got around it using by using Run>outlook /profiles.