Outlook 2016 doesn't accept password or app password

From not the community crew:
If the client is modern authentication ready, if the really old EWS function works? (Personal account EWS method?)
h t tp s :/ / as k u b u n t u . c o m / q uestions/109548/evolution-and-office-365
Host URL: https://outlook.live.com/EWS/Exchange.asmx
OAB URL: https://outlook.live.com/OABThough

The *.office365.com,  *.outlook.com, pop3.live.com, *.hotmail.com, outlook.live.com seem to have numerous ipv4 and ipv6 IPs in the d n s c h e c k e r . o r g

The imap.live.com, imap-mail.live.com, pop.live.com, smtp.live.com, smtp-mail.com, eas.live.com are mostly the same 204.79.197.212 or 2620:1ec:c11::212 from most dns in the d n s c h e c k e r . o r g

It recalls me that if the IPv6 affects since the webpage of outlook.live.com have several third party MS owned website and some are ipv4 only, some has ipv6.My ISP is dualstack but sometimes it will be only ipv6 or sometimes IPv4 only at first or lost one of them after sometime.

Perhaps I should mention that my private account @outlook.de (outlook.com account) is added as guest account to an organization. Normally this is done by creating an alias within the organization which is something like "*** Email address is removed for privacy ***" and policies are set for this alias. I only have to log in to my outlook.com account, verify with my authenticator for this private account and then verify again with my authenticator for the organization account.

I do not get E-Mails via this alias at all, so its only to sign in to their teams. Also the auth problem is only with my mobile devices third party app trying to connect via EAS to my private account, not to the alias, also with app passwords enabled. But perhaps it has something to do with that.

By the way: Since app passwords are only shown once when they are set up, it is really annoying when having a new password prompt since you have to generate a new app password just to get another authentification failure...

In fact, it is not resolved for third party applications using EWS or EAS on personal accounts. Even with 2FA swiched on and App password it is not working, it continues prompting to insert password.

I was able to sync once yesterday by changing from outlook.office365.com server to m.outlook.com server, after that I swiched back to outlook.office365.com and to my astonishment this worked. But after some minutes it shows the password prompt again. And it was with App Passwords.

Again: This is not resolved.

From not the community crew:

Since the folders of my 3 MS free personal outlook.com suffix accounts missing on the outlook.live.com and New ooutlook on and from Jan 15, and each account became normal in a interval of around a week, the eldest hotmail period account is the last one becoming normal on around Feb 3.
If the outlook.live.com and new outlook were already on Microsoft cloud or Native Microsoft sync, and remain the basic authentication.
The loading page address of the outlook.live.com have something like *ppsecure*, not the *oauth* as while logining the https://answers.microsoft.com/
I used the New outlook to login the Yahoo Japan and got them informed that I login from Malaysia several times even several days before I used it in the new outlook.
(The Yahoo Japan is not the Yahoo, but it was detect as Yahoo, and can't be logged as the default Yahoo in the New outlook. I logged in via the imap in the New outlook and outlook 2021.)
I wonder if the outlook 2021 were already logining through the Microsoft cloud or something alike, since I used to login The Yahoo Japan via the outlook 2021 imap around that period of time around August 2023 .

https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/deprecation-of-basic-authentication-exchange-online
Article 08/31/2023
We removed the ability to use Basic authentication in Exchange Online for Exchange ActiveSync (EAS), POP, IMAP, Remote PowerShell, Exchange Web Services (EWS), Offline Address Book (OAB), Autodiscover, Outlook for Windows, and Outlook for Mac.

https://techcommunity.microsoft.com/t5/microsoft-365/native-microsoft-sync-technology-migration/m-p/436039
Ross Smith IV replied to Anthony Russell ‎Apr 12 2019 06:40 AM For Outlook mobile, major feature deployment operates with a staggered rollout where we begin with consumer accounts (if applicable) and then deploy to commercial accounts like Office 365.

Ross Smith IV replied to Anthony Russell ‎Jun 25 2019 07:58 AM

We've now migrated all O365 tenants to the native Microsoft sync technology.

https://learn.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/outlook-for-ios-and-android/outlook-for-ios-and-android
Article 02/22/2023
The native Microsoft sync technology that Outlook for iOS and Android is adopting has been in use by the native Windows 10 mail client for a number of years, and in the future, will be used by Outlook for Mac.

https://support.microsoft.com/en-us/office/sync-your-account-in-outlook-to-the-microsoft-cloud-985f9e19-d308-4e85-9d1d-0c6f32f8e981
Sync your account in Outlook to the Microsoft Cloud

Outlook 2021 for Mac Outlook 2019 for Mac Outlook 2016 for Mac Outlook.com New Outlook for Windows Outlook for Android Outlook for iOS Less

Article updated: May 2023

To enhance your Microsoft 365 experience in New Outlook for Windows, Outlook.com, Outlook for iOS, Outlook for Android, and new Outlook for Mac, you can now sync your non-Microsoft accounts (including their emails, contacts, and events) to the Microsoft Cloud. This is available for Gmail, Yahoo, iCloud, and IMAP accounts in Outlook for iOS, Outlook for Android, and new Outlook for Mac. Also available for Gmail and Yahoo accounts in New Outlook for Windows and available for Gmail accounts in Outlook.com. This allows you to enjoy many features that were previously only available to those with Microsoft 365, or Microsoft Exchange Online email accounts.

It's not resolved though they marked it as such. They are lying