Consider the following scenario:
You're using the Microsoft Office 365 sign-in for Yammer.
You configure the Yammer Directory Synchronization tool to work together with your Yammer network.
You enter a verified admin’s user name and password on the Yammer Settings page.
In this scenario, you receive the following error message:
Unexpected login failure.
To resolve this issue, retrieve a temporary password. To do this, follow these steps:
Sign in to Yammer by using your Directory Synchronization dedicated verified admin account.
Click the ellipsis button (...) in the upper-right corner of the page, and then select Apps from the drop-down menu.
Locate the Windows Phone app, and then click its name.
A new window will open. You'll see a temporary password in the lower-left corner of the window.
In the Yammer Directory Synchronization wizard, use the temporary password to sign in to Yammer.
This issue occurs because the Yammer Directory Synchronization tool can't sign in to Yammer when the account is mapped to an Office 365 account.
Note We recommend that you use Office 365 sign-in for Yammer and manage Yammer users across their life cycle by using Office 365 instead of implementing Yammer Directory Synchronization. Yammer Directory Synchronization is still supported but development for it has ended. Sometime in the future, an end of support date for Yammer Directory Synchronization will be communicated and leading up to that date, all customers who are using Yammer Directory Synchronization will be required to manage Yammer users across their life cycle by using Office 365.
For more information about how to determine the best decision for your organization, go to the following Microsoft websites: