Outlook 2016 doesn't accept password or app password

Hi, thanks for answering,

I actually installed the new free version of Outlook, it took me like 5 minutes to add all my 6 IMAP accounts, some from Gmail some from my web hosting provider some from msn.com and other from my ISP, Loved the auto-configuration, super easy and I actually like the software look.

Did some testing everything works great, I just needed to turn on the notification in my OS system settings to get the email notification banner to show up.

So the new Outlook is not that bad after all like someone complained here. Yes, you get the occasional ad email once in a while, and It just takes a click to send it in the garbage.

I guess that solves it for me.

David/Gabriel,

First of all, I/we appreciate your efforts and help on this. I know you two are taking the brunt of the heat, and the thinking, of the lack of, is/are done by others behind the scene.

In a nutshell, I have a hard time believing the explanation given. I am having/had issues with multiple clients:

1. Latest GMail app for Android
2. Latest Outlook app for Android
3. Latest Outlook as a part of M365 (I added my account to my work Outlook, which is the latest build on the stable channel)
4. Older Outlook version you named

MFA is setup on all my critical accounts, including MS-based accounts. These clients are all very modern and support latest protocols, including OAuth. And if they don't work, I don't know what will.

The fact the issue is already happening to 1, 2 and 3, suggest the issue is tied to the account type and its lack of support for more advanced authentication process to your own liking, more so than the client issue alone. The data point and my personal experiences with this do not align with your assertions, so I don't think it's a matter of moving to a later version, i.e., Outlook 2021. It is possible that your team's constant tweaks of things in the last month created a fog of issues and made it impossible to pinpoint the behavior for us as users.

To your mitigation suggestions:

1. "New Outlook" that is being aggressively pushed right now, is a PWA (for those that don't know, it's like a fancy bookmark for browser website). Accessing non-MS accounts will basically allow Microsoft to be the proxy (for those that don't know, MS will become the middle man, accessing and storing your data from other non-MS platforms that you may have intentionally tried to separate). Microsoft's terms and conditions for the "New Outlook" indicate Microsoft will have rights to use those data. If Microsoft is under brute force attack as you suggested, WHY would any of us trust you to be the proxy of our other data?
2. If some of us are already having issue with the latest Outlook from M365, why would we migrate to Outlook 2021?

I keep reading in these posts about OAuth and I haven't the foggiest idea what that is.

OAuth is a modern authentication method of how cloud systems verify who you are and you are the "real you." Because of the constant hacking and that our passwords may be leaked, there is a chance hacker may already have your password. This lead to 2FA or MFA (2 factor or multi-factor authentication). Things like send a SMS message of a pin, email you a pin, or have you enter a one-time code from a security app, are those additional factors of authenticating you.

OAuth provides a mechanism to allow the initial login to handle 2FA/MFA. Some of the older apps were build before OAuth was fully finalized or implemented, so their support OAuth is either partial or missing altogether. OAuth allows a more secured method of storing information that your device or your app is authenticated or trusted, so your app or client doesn't get constantly challenged by the server everytime it tries to fetch or sync data, which happens dozens if not hundreds times a day.

The issue is not OAuth itself but Microsoft's implementation of it on their servers. To be fair, Microsoft is one of the biggest hacking targets in the world, so what it deals with on a daily basis is likely severe and more than what we can appreciate or fully grasp. Microsoft issue is that it made all these changes, unverified, on real-world production servers and yet doesn't offer a comparable method for us to workaround these issues.