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

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

• Checking the Account in Word showed the correct authentication and subscription.
• FYI outlook 2013 requires a registry setting to work with MA.
• These versions have the Logon network security setting disabled or removed from the Microsoft Exchange email account settings.
• I have a valid MS 365 subscription that includes 5 device licenses.
• Serious problems might occur if you modify the registry incorrectly.
• 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.
• The user had Office 2015 and Office 2016 credentials and Teams credentials that we deleted.

You may have to rebuild/restore your outlook folder/files which is a pain. I’d do that one step at a Outlook Login Issues Troubleshooting time, forgoing the restore of the cached files. If this box is greyed out or disabled then you need to reset the Windows Credential Manager first. Or, any suggestion on how to fix this issue, even better.

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

Microsoft Outlook 2016 and some recent builds of Outlook 2013 are not affected by this issue. Those versions have been updated to prevent the problem that is described in the "Symptoms" section. These versions have the Logon network security setting disabled or removed from the Microsoft Exchange email account mailbox not updating on IMAP settings. It requests me to login to my microsoft account. I then approve the login with my authenticator app. Then i get rerouted to the login page again to repeat the process.