Outlook 2016 doesn't accept password or app password

Unfortunately i've still got the issue. Enabled 2 step authentication but when trying to add my account back to office 2016 professional i'm still unable to log in, with both app password or my regular password. Windows credentials pops up and keeps asking to reenter but no success nop matter how many times until i cancel at which point it fails.

I've managed to add the account back on outlook, credentials requested the password 5 times before finally syncing. I log in daily so will update if there's any further issues.

I've logged in this morning and the issue comes up again. Requesting a password to be able to sync.

Go into airplane mode for a bit (or just disconnect network) then re-enable the network. May have to do it a few times. Seems like some of their servers are fixed and some aren't, and each time you connect you get a different random server.

Found the solution:

Close the Outlook Desktop App. Go to Start -> Settings -> Control Panel -> Mail -> User Mail Accounts. Select Accounts, mail *********@outlook.com (By default send mail from), select Change upside, Different options -> Microsoft Exchange window -> Additionally -> Unselect checkbox "Use precaching Exchange" and "Download shared folders". Hit "Apply", "Ok".

Open the Outlook App.

That's not the solution, just the process of disconnecting and reconnecting to exchange will solve it for a while.

Agreed. Numerous work arounds in this thread. None lasted permanently. Only MS can fix this for all of us.