I feel like this issue is getting progressively worse as the fix used to be how to fix Outlook not opening today clearing the credential manager or if it was bad uninstalling the entire Office Suite, clearing all traces and reinstalling and now we are seeing nothing helping it. Have looked all over and people have all sorts of possible solutions, but nothing we found to resolve the issue and get a new issue daily and just keep going through until it eventually works. Problem doesn’t just happen on PC’s connected to the internal network, but can happen when a laptop is remote and connected via external wifi or mobile hotspot. Today was the first time in about 2 months that I had the issue. It happened right before lunch, locked my machine, went out for lunch, came back, and logged in, this time successfully.

Outlook credential prompt loop

I disabled the Zoom and Adobe PDF plugins and it stopped prompting me immediately. My client’s Outlook will only continuously ask for the password repair PST file without data loss after MFA is enforced and Office.com has been logged in. It would be nice if it distinguished between your password and the app password. You may have to rebuild/restore your outlook folder/files which is a pain. I’d do that one step at a time, forgoing the restore of the cached files. Not sure if it has to do with being an onmicrosoft.com account that has no domain assigned to it.

Loop of 'Sign in to your account'.

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. The repeated issue logging in started after I enabled the modern authentication in the Office 365 administration panel. The user could use the Windows mail and calendar apps but Outlook wouldn’t connect and kept prompting for a password. Checking the Account in Word showed the correct authentication and subscription.

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 Fix Outlook and Office 365 Errors 2025 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.

• If this box is greyed out or disabled then you need to reset the Windows Credential Manager first.
• I created a new Outlook profile, and then the old one started working.
• Out of 140 staff the problem seems to occur once every 2-3 weeks on average.
• 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.
• I had this exact issue on another machine, that after 2.5 hours on the phone with MS support (via Zoom), the solution was to uninstall MS Office 365 and reinstall it.
• I experience the issue myself as well, every once in a while.
• I’ve seen this happen when the time and or date is wrong on the machine.

Changing Outlook Security Settings:

If this box is greyed out or disabled then you need to reset the Windows Credential Manager first. @Microsoft, given the level of attention the community has given this issue, I hope you come up with an update soon. We have been experiencing the exact same issue for months now.