Phone support is at least actually looking into this. They semi-admitted there might be a problem, since webmail was having difficulties too! Supposedly they're gonna call me back in 24-78 hours.,if they do, that'll be the first time in 20nyewrs they've kept their promise!
My software and operating systems are all fully updated. Outlook on the two Windows 10 desktop computers (one Win 10 Pro, the other Win 10 Home) both have the exact same problem. They are both configured correctly and are not set to prompt for login credentials. In fact, when the login prompt comes up, the IMAP server name, my user name, my password and the "Save password" checkbox are already propagated with the correct information. Outlook on my Android phone requests account information every 3 or 4 days, as it seems that's how long the email access token expiration is set to.
i'm offered tokens on several sites but choose the login/pw route, eliminate the tokens & the problem will probably go away.
fwiw: i use win10 pro, office/outlook2016 without any issues.
