You have a server that is running Microsoft Forefront Unified Access Gateway (UAG) 2010 Service Pack 1.
You have a portal that has the following features enabled under Advanced Trunk Configuration:
Enable users to change passwords
Notify user <number_of_days> Days Prior to Expiration
You log on to the portal by using a user account that has an expired password.
In this scenario, your log on may be unsuccessful, and you receive the generic "Authentication Failed" error message. Additionally, you are not prompted to change your password.
This issue may occur if the user account is located in a different domain from where the Unified Access Gateway computer account is located, and there is no full trust relationship between the domains.
To resolve this problem, install the service pack that is described in the following Microsoft Knowledge Base article:
2710791 Description of Service Pack 2 for Forefront Unified Access Gateway 2010
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates