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Office 2016 For Mac Not Signing In

Office 365 and Office 2016 are pretty much doing away with the Product key in favor of a user login. Each user will have 5 activations and as long as they have separate user profiles you can set this up once and as the use the Office applications they will be required to login at least once a month to keep it activated without login prompts. Starting from Office 2016 for Mac version 15.33, unsecured endpoint traffic is blocked in authentication flows. Cause for symptom 2 Starting from Office 2016 for Mac version 15.33, the authentication method no longer selects NTLM authentication when multiple WWW-Authenticate headers are present in the response.

Office 2016 For Mac Not Signing In -->

Note

Office 365 ProPlus is being renamed to Microsoft 365 Apps for enterprise. For more information about this change, read this blog post.

Symptoms

When you try to activate or sign in to any of the Microsoft Office 2016 applications after you install the version 15.33 update, you receive a blank authentication screen. Additionally, you may see any of the following symptoms.

Symptom 1

The following issues occur in the Unified Logging Service (ULS) log:

Office 2016 For Mac Not Signing Invitation

  • The server has redirected to a non-https URL.
  • Errors occur in Azure Active Directory Authentication Library (ADAL) authentication.

To locate the ULS log, open Finder and browse to the following path:

~/Library/Containers/com.microsoft.<Application>/Data/Library/Caches/Microsoft/uls/com.microsoft.<Application>/logs

Note <Application> represents the name of the application that you are troubleshooting.

Symptom 2

You notice that in an HTTP trace, the server response includes multiple WWW-Authenticate headers, such as the following:

WWW-Authenticate: Negotiate

WWW-Authenticate: NTLM

Cause

The symptoms occur for the following corresponding reasons:

Cause for symptom 1

Starting from Office 2016 for Mac version 15.33, unsecured endpoint traffic is blocked in authentication flows.

Cause for symptom 2

OfficeNot

Starting from Office 2016 for Mac version 15.33, the authentication method no longer selects NTLM authentication when multiple WWW-Authenticate headers are present in the response. The issue occurs when the selected authentication method is unsuccessful.

Resolution

Resolution for symptom 1

Configure all authentication endpoints to use the Secure Sockets Layer (SSL) protocol.

Resolution for symptom 2

Install the September 2017 update for Office 2016 for Mac version 15.38.

Office 2016 For Mac Not Signing Instructions

More Information

Office 2016 For Mac Not Signing In

Office 2016 Mac Sign In Not Working

More information for symptom 1

Office 2016 For Mac Support

The resolution applies when you use Microsoft Active Directory Federation Services or non-Microsoft federation solutions.