Outlook 2016 doesn't accept password or app password

Well...alas, not fixed. Multiple "authentication error" ,this morning. Email client: 9Folders. 2 Outlook.com accounts using Exchange Activesync. Frustrating.

"New Outlook" has new terms and condition, and by using it, you agree to send and share all your emails and 3rd party account data with Microsoft. So think and read that before you opt to use it. "New Outlook" on Win11 is a PWA. For MS accounts, it probably doesn't matter, BUT if you access any non-MS accounts, it means MS cloud will be the middle man accessing your non-MS account data and refurnishing it to you on your screen. It's very very different than the Outlook desktop which is a local client. "New Outlook" is a cloud client.

If Microsoft (MS) is going to eventually make New Outlook the only MS mail "client" offering, "replac[ing] the Windows Mail App and will be the same app that eventually replaces Outlook Desktop in M365", as Gabriel Bratton has stated on page 43 of this thread, and presumably the ultimate plan, the warning (above) to which I reply here from page 13 is very important when considering whether to use New Outlook or not. It's rather concerning for us in regards to privacy and security, especially for non-MS accounts and e-mails, being proxied and identifiably linked to a New Outlook user through some sort of MS cloud e-mail so-called "client" (server). If this is how New Outlook is going to function, it will not be a viable option for us either.

Gabriel,

This baffles me. My company provides me with an Office subscription through my [companyname].onmicrosoft.com Microsoft account. We are explicitly instructed to not treat this account as an email account, and to not add it to any email clients in order to not create any mix-ups. One of my colleagues didn't follow these instructions, accidentally sent a customer an email from his onmicrosoft.com account, and now the customer (and everyone who is ever in CC) keeps using that account to contact him instead of his company email account.

Are you telling me that in my paid Office 365 suite I can't avoid ads (particularly those shadily formatted to look like emails) unless I add my corporate Microsoft account as an email account in Outlook?

Unless I completely misunderstood you, this is an amazingly daft strategy to squeeze a few cents of ad revenue out of paying customers. Microsoft have some products that are essential for any business, but the Outlook email client is not one of them. The day the classic Office apps are phased out (or develops serious issues that can't be resolved) will be the day we will cancel our Office 365 subscription.

It does not work with MS Outlook 2013/16 what more even two accounts side by side can be different. We well into 3d week of this issue and solution don't seem to be in sight. Sadly. This thread alone is on 44 page! Not like it surprises me much. MS developed quite a fragmentation of Win10/11 systems. Given they on same win xx and same build it still will be fragmented in terms of behaviour. So, things working on one will not work on other PC.

Gabriel- if I’m understanding your question correctly, when I add my Msoft Outlook credentials in the iOS “add another email account” as an Outlook.com account instead of a Msoft Exchange account, it is more stable - I don’t think I’ve ever gotten an incorrect password message, and I have full email, calendar, contacts across my iPad and W10 MExchange 365. Please let me know if your team would like to reach out directly.