Outlook 2016 doesn't accept password or app password

Authn column should show Bearer* (English version, connected to 365 Exchange mailbox)

So should I resign myself? Outlook 2016 won't support this blessed modern authentication? I checked everything and more, the registry keys to enable modern authentication, they are all enabled. I do not know what to do.

In your case, are you having problems with the password request we are discussing?

It happened to me only once. I've been using the same Outlook 2016 since 2020 and never got a problem with it.

This year, my Outlook 2016 on Windows 10 suddenly prompted me for password. Nothing's changed recently (no password change). I clicked cancel, exited Outlook and relaunched it. Things went back to normal. It hasn't happened again since that day (a few weeks ago).

As a side note I had a problem configuring Outlook 2016 for a new user. It just wouldn't connect to the mailbox. I spent several days troubleshooting which includes adding registry entries (meant to be for Outlook 2013) although I knew 2016 didn't need it. No dice. After a few days, my user retried connecting Outlook 2016 to her mailbox and bam... it worked. I haven't made any changes on user's PC since the previous failure (unable to connect to user mailbox). That makes me believe there's something going on on the back end. Who knows what it is.

MS people are trying to mislead us or they don't know better.... and hope people don't catch the details. OAuth is supported in several versions of Outlook - it's not new. The screen you showed indicate you are logging into a work or organization account, hence the outlook.office365.com domain and you are showing Bearer*. This means your account should be properly authenticated.

If this was a consumer account, i.e. Hotmail, Outlook.com, Live or MSN mail, then the OAuth will not happen. To me, it's not Outlook itself that is missing the OAuth related code, but the server side is rejecting OAuth like an account is not provisioned for that.

The MS people here kept saying OAuth is supported on the consumer accounts, but then they stop short of saying what protocol. If you read through all the posts (ironically, I used Copilot to read it for me just to make sure), OAuth is only supported on IMAP protocol on the consumer accounts - that's only thing they confirmed. All of us are dealing with Exchange/EAS/EWS issues and I am nearly certain those protocols on the consumer accounts are not provisioned with OAuth or at least not universally to all accounts.

The end game is to force people to buy Office 2021 for those hardcore users... or force people to use free "new Outlook", so MS can intercept and collect all of your non-MS data. It's more of a strategy that they laid out to force our hands. Your best option is to move your data off MS systems if you have privacy concerns.

In my case in Italian it does not have the writing Bearer* but Not encrypted*, what does not encrypted mean? Am I using modern authentication?