Outlook 2016 doesn't accept password or app password

If I look through the entire history of this thread and MS' feedback, here is my takeaway:

1. Basic Auth is going a way, BUT NOT YET
2. The current denial is related to Basic Auth
3. MS implemented some security measures in 1/2024 because of brute force attack, so the server will now block Basic Auth if it senses "irregularity" in access pattern.

But until Basic Auth is completely and officially removed, can we have some access reliability? I am sure many folks including myself have already spent way too much time debugging this. We just need a period of normalcy. MS needs to fix/improve the new security measures, so it doesn't falsely block legitimate login attempts. This will give us time to address the "missing/non-working" OAuth needed for EWS/EAS.

On the subject of region, I recall that when this whole mess began, Thunderbird repeatedly threw an error about a time zone issue (unfortunately, I failed to screen grab it). I logged into my Hotmail account via outlook.live.com to confirm the time zone and it was set to an incorrect region. I would change it, but hours later, it would revert back to the incorrect zone and Thunderbird would again throw the error.

I'm just adding this info here in the hope that it might be useful for MS to finally fix this problem plaguing so many of its customers.

Hi Gabriel,

The timing of 23-24 Jan 2024 of this unresolved issue I feel is significant. Recent comment about region is also relevant. There must be a commonality with those experiencing the issue vice those not. Since it doesn't seem to hit major media tech sources it is not generating enough attention. Someone changed something, somewhere, possibly with alias or certificates. Changes could have been made outside of the Outlook team you access. If basic auth being deprecated, that means it's not completely disabled and shouldn't be affecting those paying for M365 intentionally. Pings and tracert responsive for 2-3 tested addresses for m.hotmail.com and m.outlook.com. Traces drop off at 13th hop, timeouts but concludes by hop 17. Of course not knowing what normal hop count and speed looked like before 23 Jan 2024. See certificate type error when IP address used vice m.hotmail.com

Also please, elevate this issue and ask a team other then the one your consulting. Let us know. Thanks

Regional or timing issues, but either way, an issue. Cannot get into either of my outlook.com accounts, 9Folders email client, eas server. Need to use desktop access only. While connection has been spotty for 6 weeks now, today is a complete loss of connectivity. Truly tough to carry on my business, without access on the go.

It feels to me like this is a regional issue somehow. I have two accounts set up using the Gmail app on Android. One of them seems to sync Ok for a certain period while the other isn't working. Then I maybe get some overlap where both work and then the other fails. Potentially something changes with GLB-type services? So maybe certain region MS data centres have the issue and certain others don't?

Both are using app passwords as the switch to modern Auth just fails to display a login page.

Since finding this thread, I've stopped trying to re-auth or use new app passwords and the accounts just sync for part of the day and then sit there saying sign-in required for the rest of the time. Frustrating to say the least.