Applies ToOutlook 2016

Last Updated: October 26, 2017

ISSUE

After Modern Authentication is disabled, users may intermittently get prompted for their credentials in Outlook 2016 and have to repeatedly enter their username and password.

Note: Fiddler traces reveal 401/403 authentication failures to this endpoint: "https://outlook.office.com/api/v2.0/Me/InferenceClassification"

This scenario can occur if Focused Inbox and Modern Authentication for the tenant is turned on and then Modern Authentication is turned off. When this happens, Focused Inbox has already started working and keeps trying to connect resulting in these credential prompts.

STATUS: WORKAROUND

Workaround #1: Turn Modern Authentication back on.

Workaround #2: If you want to keep Modern Authentication turned off, but avoid the credential prompting problem, do the following:

  1. Turn Modern Authentication back on temporarily.

  2. Turn Focused Inbox off and wait until all users who are using Focused Inbox get the "off" signal.

  3. Turn Modern Authentication off.

Icon Experts (brain, gears)

Ask the experts

Connect with experts, discuss the latest Outlook news and best practices, and read our blog.

Outlook Tech Community

Icon Community

Get help in the community

Ask a question and find solutions from Support Agents, MVPs, Engineers, and Outlook users.

Outlook Forum on Answers

Icon feature request (light bulb, idea)

Suggest a new feature

We love reading your suggestions and feedback! Share your thoughts. We're listening.

Find out how

Fixes or workarounds for recent issues in Outlook for Windows

Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Find solutions to common problems or get help from a support agent.