Outlook 2016 doesn't accept password or app password

I am seeing the same issue with Office 365 version of Outlook. I added one of my test account (on Hotmail), and still get the authentication prompt, though less frequently as the older classic Outlook desktop version. Therefore, the issue is not resolved as MS suggested by going to Outlook 2021 or later. However, adding the same Hotmail account to Outlook for Android doesn't get those prompts.

I hate Outlook for Android but since its accessing my work data, which is also on Microsoft infrastructure, I am less concerned about data privacy. Outlook for Android has anti-competitor/anti-trust worthy behaviors. Proper syntax Google Meet URL in calendar invites are not clickable but Teams' is clickable. All my coworkers that attend Google Meet meeting have the same issue. Amazon Chime meeting URL is also not clickable. I ended up forwarding those Google Meet and Amazon Chime meeting invites to my Google account which then showed up in Google calendar and they magically become clickable and launch those meeting apps accordingly.

I am really disgusted with Microsoft's approach these days. As pro-tech as I am, the government needs to step in.

Thanks for the replies.

It turns out, the problem was resolved by changing a registry key (via Registry Editor) as follows:

HKCU\SOFTWARE\Microsoft\Office\16.0\Common\Identity

EnableADAL 1

Previously, EnableADAL was set to 0.

I hope this helps.

For all of you using BlackBerry Hub+!

I just got this mail from Kenneth of the support team:

"We have pushed an update to the Google Play Beta track that now allows you to add your Microsoft email account with modern authentication. If you are not currently part of the beta program but would like to try this update and provide feedback, please go into Google Play on your mobile device, search for both the BlackBerry Hub+ Services and BlackBerry Inbox, and opt into the Beta program. If you currently have your Microsoft account configured in Hub, please remove it and then readd the account. After entering the email address in the Add Account flow, you will be asked for a password, below which is a button labeled "Sign in with Microsoft". Click this button and use the Microsoft prompts to login, accept any permission dialogs, and you should be able to complete the workflow and now access your email. This update was just pushed out today, Aug 29th, so it could take sometimes a day or two for you to see the update."

Just to let you all know.

If you care about your data privacy, do not add non-Microsoft account into the New Outlook. You will give it permission to access, collect and store those non-Microsoft data in Microsoft Cloud for their use. This is made very clear in the terms and condition for those of that either read them or write Ts&Cs for a living.

If you are using New Outlook to access your free MS account, it's probably OK because MS already has your data, but be cautious about other accounts like Google's or Apple's.

I also saw another weird behavior that if I run setup on New Outlook and if it detects Classic Outlook is installed, it somehow pulled those account setup information automatically without even asking, so if you had a non-MS account on Class Outlook, this could be another risk. I am really surprised at the amount of **** Microsoft is try to pull these days. They are hellbent to get your data one way or another.

I have posted about similar experience a while ago. I added my Hotmail account to my work Office 365's desktop Outlook (not pop3). I was having the same auth issue. While some of the MS people on these forums try to be helpful, I generally don't believe 100% what they are saying My experience has proven they are not right in many cases especially now that Microsoft is making a lot of changes to all of their products.