Outlook 2016 doesn't accept password or app password

Based on Outlook and other apps are unable to connect to Outlook.com I updated my Outlook 2013 (on Win11) to the latest version a few days ago. Opened Outlook and it just worked (like it used to). I thought the problem was solved, but a few hours later, the password popups began again. I have 5 Microsoft-associated email accounts so it's a lot of popups. Outlook is back to insisting on passwords multiple times per account on app launch and intermittently throughout the day. I hope they resolve their server issues soon, Outlook was wonderful until the 23rd of January.

I am getting tired of this. I think I am going to have all my MicroSoft related Email accounts deleted or just stop using them and switch to another Email provider. Maybe if we all do this, they'll get upset because of the loss of AD revenue and fix the issue. I am starting to think this is all a scheme to get us to buy a 365 subscription. All other providers work fine with Office 2013 until MicroSoft decides to do something that breaks them. Let's all stop using Outlook/Exchange related Email accounts (Outlook, Hotmail, MSN, etc.).

This discussion forum itself is having an issue. I'm seeing everyone's display name as A. User.

Anyway, in my case, I have been connected to my 365 Exchange mailbox for years and NEVER been prompted for password EVER... until today. I'm using Outlook 2016 with up to date patches. Today I see a prompt to choose if my account is Work/School or Personal account. I click Cancel (without choosing anything or typing my password). I then close Outlook and get back in. Outlook does not ask for anything. It connects just fine. It's back to normal now.

I'd be really upset if my users start getting prompts. Many of them don't remember their password. This means I have to reset many users password because of this crap.

Yes, most of yesterday was fairly good but started to have issues again towards latter part of the day.

I want to raise another issue people may not be thinking about. This whole server-side change is in the name of "improving security" but its having the opposite effect! I have entered my credentials more times since 1/23 until now than I think I have in the last 5 to 10 years combined. Not sure if MS has thought about this... what if someone is unlucky and has some type of virus, trojan horse or malware that is keyboard-logging or monitoring what you are typing... Your password could have been expose to these risks. I tried to just cancel the pop but I've noticed I need at least enter the credential once in a while, or it will stay unauthenticated for a long long time.

We are coming to one month anniversary of this issue. Can MS clarify the current game plan, and if we should start looking for alternative email platforms to transition to?

To clarify, this is on an iPhone 13 installation when choosing either Microsoft Exchange vs. Outlook.com. The Microsoft Exchange option didn’t even recognize the server.