We are moving our on-premise Exchange server to an Exchange 365 server. Basically going to form, users connecting to outlook.com without issue.. My question involves at least two W10pro systems with Outlook 2016 installed on them. I tried making new profiles in their mail setup (manual setup to outlook.com or EAS) and have them point to the outlook.office365.com server, but they fail trying to connect (see attachment). Their credentials are correct as they work on outlook.com and I can create a new profile on my laptop (also W10pro and Outlook 2016) that connects to the 365 server. I also tried logging in as a different user on their systems and cannot get an account to sync up properly.
Any thoughts what I can do on those systems?