PROBLEM:
Using Office 365 with Microsoft Small Business Server 2008.
Using Office 365 with Microsoft Small Business Server 2011.
Outlook prompts for username and password for Office 365 in SBS Domain.
SOLUTION:
Use the Exchange Management Shell to remove the Autodiscover Virtual Directory.
1. Open an elevated command prompt and back up the IIS configuration using the following command.
%windir%\system32\inetsrv\appcmd.exe add backup "Pre Removing Autodiscover"
2. Retrieve the current autodiscover virtual directory.
Get-AutodiscoverVirtualDirectory | fl Name, Server, InternalUrl, Identity
*Make note of the Identity value for the next step.
3. Remove the autodiscover virtual directory.
Remove-AutodiscoverVirtualDirectory –Identity <identity value retrieved above>
You will have to confirm by typing a "Y".
4. Check that the autodiscover virtual directory is gone.
Get-AutodiscoverVirtualDirectory | fl Name, Server, InternalUrl, Identity
This should return nothing.
5. Open Outlook, hold the CTRL button, right-click on the Outlook icon in the system tray, and select Test E-mail AutoConfiguration. Enter your email address and password and click the Test button. The results should come from the Office 365 server.
CREDIT:
Thanks to Mark Berry at MCBSYS (http://www.mcbsys.com)