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 the profile and clearing the 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.

Additional resources

Please help can't afford a new computer if I throw this one against the wall. Yeap, you describe it exactly and unfortunately we still don’t have an answer. Closed the window without entering anything and Outlook returned to ‘Connected to Exchange’. Office 2016 is already Modern Authentication aware so APP passwords are not required.

Microsoft Office 365 Endless Authentication Loop Issue

• Native IOS and Android Mail apps will require the APP password or users can use Outlook for IOS/Android which is Modern Auth aware.
• We’ve got a support case opened with Microsoft on this one but it’s been open for about 3 months.
• There doesn’t appear to be any pattern to the issue occurring or the problem being limited to any specific computer or user.
• I checked my MS account info page, subscription is fine.
• The user could use the Windows mail and calendar apps but Outlook wouldn’t connect and kept prompting for a password.

When we opened the old, existing profile it didn’t ask for ANY authentication, it just started working. Modifying the Outlook profile by using the "Profiles" registry path is not supported and may cause your Outlook profile to be in an unsupported state. FixTechGuide mailbox repair steps Serious problems might occur if you modify the registry incorrectly. Before you access it, back up the registry for restoration in case problems occur. We are looking at using conditional access policies where a user with a Domain joined PC is not prompted for MFA.

Outlook stuck in an MFA loop

The modern authentication troubleshooting user had Office 2015 and Office 2016 credentials and Teams credentials that we deleted. We checked with Word that the account was connected–it was and the we opened Outlook and it immediately connected. We too have been seeing this more and more, all W10 on O365, although we use Okta as our MFA. 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. 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.

Outlook 365 Password Prompt Issue on Windows Desktop

You can reply to reactivate the question if you decide you want to continue. Let's disable faulty add-ins in Outlook start by answering a few simple questions to understand the problem. We have been experiencing the exact same issue for months now. I experience the issue myself as well, every once in a while. On the off chance that none of these things solve this issue for you, please contact our support team at