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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. To locate and view the registry setting for Anonymous Authentication in the Outlook profile, follow these steps. This issue can occur if the Logon network security setting on the Security tab of the Microsoft Exchange dialog box is set to a value other than Anonymous Authentication. 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.

Additional resources

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. I checked my MS account info page, subscription is fine. 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.

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.There doesn’t appear to be any pattern to the issue occurring or the problem being limited to any specific computer or user.We are looking at using conditional access policies where a user with a Domain joined PC is not prompted for MFA.I checked my MS account info page, subscription is fine.When we opened the old, existing profile it didn’t ask for ANY authentication, it just started working.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. mailbox not updating on IMAP 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

I do NOT have this issue with the other laptop, an iPad, a MacBook Pro and Office 365 Sync Errors Fix tablet. So figuring that was the same issue here, I did the same thing. I'm also getting Error 29, which the MS support rep couldn't explain to me. I even tried disabling my anti -virus while authenticating, that didn't work.

Outlook 365 Password Prompt Issue on Windows Desktop

You can reply to reactivate the question if you decide you want to continue. Let's fix Outlook after Windows update issues 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