Outlook 2016 doesn't accept password or app password

Yeah same for me, it works a few hours and came back again

Definitely not solved. It worked for about 4 hours and now I have failures again.

Problem is solved ? Looks like it's working for me again.

I've been following this thread since my Android phone with the gmail app stopped syncing emails with my @outlook.com personal account, as well as contacts, and it constantly requested credentials.

When the problems started, I deleted the Exchange account on the phone, and tried to re-add the account which failed repeatedly over the last week. Finally this evening, it managed to successfully connect and emails + contacts synced to my phone.

My account has 2FA enabled, but as previously, I set up a new app password and used this when adding the Exchange account in Settings -> Password and accounts -> add account -> Exchange: ******@outlook.com, set up manually, using the app password, and changing the Server value to m.outlook.com. This was key item as previously I was using eas.outlook.com and assumed it would still be this. When selecting Next, it failed but going back and tried again about 3 or 4 times and it eventually succeeded.

Fingers crossed the account continues to sync without issues.

Please stop saying there is no issue just because you are not having it. I have 2FA setup, in fact, MFA - including email, SMS and OTP. The OTP approach is FORCED on Microsoft managed accounts. It was rolled out last year in a very forced way. What you don't know is that most commercial insurance companies won't write a policy without 2FA/MFA being enabled!! Insurance companies force businesses to make declaration as such. The Microsoft management dashboard even has an audit function to show and confirm users have OTP turned on. My devices are all running the latest or latest-1 version of the OS, and my Outlook clients are all latest version with modern auth, and I am having this issue. My personal account also has MFA enabled with OTP generated by the same OTP app. You kept saying if the infrastructure is "managed correctly" which again ignore the fact that many small to mid-size businesses have Microsoft managed accounts as in my case with my work.

I wish you would stop saying this is a limited issue and suggest people don't have 2FA/MFA setup is the cause. It's very irresponsible to spread this information and discount people's real-world experiences and pain.