I experience the issue myself as well, every once in a while. Tried CC cleaner to clean up registry and everything -- also keep in mind this resolve Outlook not sending emails fast is a fairly recent reinstall of windows. I am unable to stay signed in to my work account on Teams, Outlook, Office365 for more than 5 minutes.

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 Outlook Stuck on Synchronizing Folders 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'.

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. 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’. I created a new Outlook profile, and then the old one started working. I wonder if the compuer cached a new logon token or something that the old Outlook profile could use. Also, during the new profile creation, I was only prompted for a password and not for MFA.

Resetting the Windows Credential Manager:

When we opened the old, existing profile it didn’t ask for ANY authentication, it just started working. Office 2016 is already Modern Authentication aware so APP passwords are not required. Native IOS and Android Mail apps will require the APP password or users can use Outlook for IOS/Android which is Modern Auth aware. FYI outlook 2013 requires a registry setting to work with MA. Where I work, we have a new sandbox tenant to make tests before FixTechGuide support for Office 365 official deployment. I tried registering the account to my Outlook Desktop app and for some reason I am in a credential prompt loop that always asks for it anytime I input my password.

• 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).
• This is now the 2nd machine that presents the same issue.
• I disabled the Zoom and Adobe PDF plugins and it stopped prompting me immediately.
• Clear the Windows Credential manager or recreate the users Outlook profile.
• I’d do that one step at a time, forgoing the restore of the cached files.

Changing Outlook Security Settings:

Hi, my office 365 account used to work with my desktop apps, I have confirmed with my admin system twice already that I have the appropriate license and everything is enabled but i keep getting stuck in this loop. We are looking at using conditional access policies where a user with a Domain joined PC is not prompted for MFA. 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. The 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.