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 Outlook Not Sending or Receiving Email 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

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 rebuild Outlook data file quickly the profile and clearing the credential manager.

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:

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 Fix Outlook Not Opening After Windows Update 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.

• It would be nice if it distinguished between your password and the app password.
• We have been experiencing the exact same issue for months now.
• Create your account and connect with a world of communities.
• The user had Office 2015 and Office 2016 credentials and Teams credentials that we deleted.
• We too have been seeing this more and more, all W10 on O365, although we use Okta as our MFA.
• Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.

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.