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

The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action. 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.

Microsoft Office 365 Endless Authentication Loop Issue

• 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.
• Before you access it, back up the registry for restoration in case problems occur.
• On the off chance that none of these things solve this issue for you, please contact our support team at
• Clear the Windows Credential manager or recreate the users Outlook profile.
• Also, during the new profile creation, I was only prompted for a password and not 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 connection to Microsoft Exchange is unavailable.
• We checked with Word that the account was connected–it was and the we opened Outlook and it immediately connected.
• Office 2016 is already Modern Authentication aware so APP passwords are not required.

You may have to rebuild/restore your outlook folder/files which is a pain. I’d do that one step at a solve Office 365 mailbox sync delays 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 modern authentication troubleshooting 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

So not doing anything at all even seems to work. Which to me sounds outlook ost vs pst Repair like the issue is service side, not client side. Problem doesn’t just happen on PC’s connected to the internal network, but can happen when a laptop is remote and connected via external wifi or mobile hotspot.