After you run the Microsoft Online Services Diagnostics and Logging (MOSDAL) Support Toolkit, the Active Directory Federation Services (AD FS) diagnostics log shows the following error:
Microsoftonline.com could not be accessed.
This log is located at Admin_Applications\SSO_Diagnostic_Tests\ADFSDiagnostic.txt.
Additionally, when you use single sign-on (SSO)-enabled user ID credentials to sign in to Office 365 resources, the client computer may be unable to resolve IP addresses for microsoftonline.com.
This issue may occur if there are network problems that limit access to Office 365.
To resolve this issue, see the following Microsoft Knowledge Base article:
How to troubleshoot computer issues that limit Office 365 rich client authentication
Still need help? Go to the Office 365 Community
website or the Windows Azure Active Directory Forums