We run an exchange server on-premise in New Zealand. We have a branch office in the USA. For years I have used ActiveSync to connect their Outlook to our Exchange remotely (using TeamViewer for the initial setup). Now we have a new user in the USA and their PC uses Outlook 2019. I cannot make this connect to Exchange. I know that Outlook 2019 doesn't use ActiveSync anymore but nothing else I try can make it connect either. I have checked the Auto Discover using the Microsoft Remote Connectivity Analyser and it seems to be functioning ok.
What else should I be trying? Can I buy a license for Outlook 2016 or earlier? Is there a registry setting I can change for Outlook 2019 to make the ActiveSync work?