But by mistake, I turned on MFA for the admin account, and then when I logged in again, it prompted me to use Microsoft Authenticator. The bad thing is this account was not registered with Microsoft Authenticator, so I couldn't see any codes inbox repair tool alternative in the authenticator. And there were no other login options, and I was stuck in a login loop. This is now the 2nd machine that presents the same issue. I have a valid MS 365 subscription that includes 5 device licenses. On the main machine where I have been using the suite, now my account is deactivated and if I try to authenticate, it looks like it works but then get the "Fix", "Authenticate", "Activate" or "Resolve" buttons, all of which do nothing.

Outlook credential prompt loop

In the instances that this occurs the effected user is not new to MFA but has been running it for at least months. The problem appears to randomly affect users (I’ve had it affect myself once too), and the only solution appears to one of (or a combination of) the options in the OP. Out of 140 staff the problem seems to occur once every 2-3 weeks on average. In this case are you saying that there is a password prompt for the users credentials? Clear the Windows Credential manager or recreate the users Outlook profile. In fact if you just turned on MFA and you were not using MFA before you usually end up having to rebuild Fix Outlook and Office365 Sync Issues the profile and clearing the credential manager.

Loop of 'Sign in to your account'.

Which to me sounds like the issue is service side, not client side. A vast community of Microsoft Office365 users that are working together to support the product and others. I’ve seen this happen when the time and or date is wrong on the machine. It’s not caused by an out of sync MFA prompt as I have personally looked at a number of cases with the user as stepped through it. In each case the fix has either been one of the above items or a combination of them. There doesn’t appear to be any pattern to the issue occurring or the problem being limited to any specific computer or user.

Resetting the Windows Credential Manager:

If you are saying that they are getting multiple MFA prompts then this is an out of sync issue with the wrong code being used. We’ve got a support case opened with Microsoft on this one but it’s been rebuild Outlook data file quickly open for about 3 months. Unfortunately when the problem occurs they’ve asked us to ring straight away but of course you can never get them instantly (we’ve just been given someone’s direct number now). To make a long story short we’ve since been asked to collect Outlook logs and install Fiddler to capture additional logging. Initially, this account didn't have MFA turned on, and I was able to log in.

• I even tried disabling my anti -virus while authenticating, that didn't work.
• Right now we have it set to prompt when a user is not on any of our corporate networks or they are using a mobile device.
• I cannot find the phone number again to contact MS Office support (eventually they were helpful, but only after insisting they help!), I'm in the Netherlands so if someone has a phone number, I'd love to get it again.
• I do NOT have this issue with the other laptop, an iPad, a MacBook Pro and tablet.
• If you are saying that they are getting multiple MFA prompts then this is an out of sync issue with the wrong code being used.
• You may have to rebuild/restore your outlook folder/files which is a pain.
• We had the issue where Outlook 2016 kept prompting for a password for an Office 365 user whose laptop was connected to their Office 365 account using Windows 10 Pro.
• A vast community of Microsoft Office365 users that are working together to support the product and others.
• In each case the fix has either been one of the above items or a combination of them.

Changing Outlook Security Settings:

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Create your account and connect with a world of communities. I cannot find the phone number again to contact MS Office support (eventually they were helpful, but only after insisting they help!), I'm in the Netherlands so if someone has a phone number, I'd love to get it again.