Outlook 2016 doesn't accept password or app password

I don't believe the POP protocol is being deprecated by Microsoft, but I will also never use "New Outlook" for the same reasons as far as privacy and security is concerned as outlined in its Terms that gives them rights to all your data, including NON-MS accounts as it functions as a proxy. I switched from POP to IMAP years ago to protect myself from data loss from local hardware failure back when Outlook Express/Windows Live Mail was what Microsoft offered, but I also made the move to archive all mail in Gmail, moving hundreds of thousands of messages as Microsoft now has 1/3 the storage as Gmail and at that time Gmail allowed far more nested folders than Outlook.com. Perhaps this is no longer the case, but I will never go back. I now have message filters in Thunderbird that moves all messages out of Microsoft email accounts into Gmail for archival, so I use zero Microsoft storage and will not pay them for any either. At that time, I had no way to automate transfer of my POP folders so I had to manually create them on the IMAP server. This was tedious to say the least. Anyway, while I am not familiar with transferring local POP data out of Outlook xxxx, you should be able to continue using POP with a different client such as Thunderbird. The trick will be getting your folders and data in another client.

My understanding is that it's due to authentication, which, apparently, cannot be reset, even with registry editing in some cases. Your case may be that one of the 4 has a different authentication setting.

If you access via webmail, does it still not work? And have you run the repair procedures on the mail files? You'll want to eliminate the possibility of an unrelated problem with your files.

The thing I don't get is that, despite having four MS accounts (Exchange) hooked up to my Outlook 2013 (Windows 7), only one of them isn't processing mail. Why aren't all affected?.

Gummo;

In my case, I don't have the trouble on my phone. I have it on my computer. Deleting and re-installing would mean re-installing with IMAP, not POP on the "new Outlook", since they have blocked POP systems. My particular irony is that my master MS account is one of my hotmail accounts, so they have torpedoed the hotmail compatibility for 2013/2106 (which I paid for), making it impossible to re-install on 2013/2016 with my MS account.

Conversely, I have to do the painstaing migration of POP to IMAP on the "new Outlook", and throw away my local management of all my old folders and storage. I am forced to pare down or pay them premiums for extra cloud storage. This, although I paid for cloud storage with my permanent versions, which they then rescinded. I already went one round with them over cloud storage of photos, which I refuse to do, as that would result in exorbitant cost for the updated storage necessary.

They aren't providing solutions because A) They don't want us to manage our own data and B ) they want to nickel and dime us into more and more levels of paid subscription, which is really more of a prescription than a subscription. Looks great in their Board Room, but has nothing to do with us.

At this point, they simply have me angry, and wanting, with every fiber of my being, to stop any and all subscriptions with them.

On the other hand, if they wanted to, they could solve all of this in 8 seconds. ALL of it.

I will try this. Thanks so much. Will report back.