A customer tries to check connectivity to their Hosted Exchange mailbox using Microsoft Remote Connectivity Analyzer at https://www.testexchangeconnectivity.com. The Analyzer reports autodiscover test failed with the following error message:
The URL specified in the location HTTP header was in an unexpected format. The expected path should be /Autodiscover/Autodiscover.xml
Indeed, in typical POA configuration autodiscover path is /AutodiscoverProxy/Autodiscover.xml. Microsoft Remote Connectivity Analyzer only expects /Autodiscover/Autodiscover.xml, however Outlook may work perfectly well with /AutodiscoverProxy/Autodiscover.xml and mail users are not affected by the problem Analyzer reports.
Actually, as long as Outlook works correctly with configuration created by POA the problem does not require resolution.
Instead of Microsoft Remote Connectivity Analyzer you may use Outlook's built-in 'Test E-mail AutoConfiguration' feature described in the Microsoft KB article http://support.microsoft.com/kb/2581088#Bookmark7 - check Step 2: Use the Test E-mail AutoConfiguration tool to determine whether Outlook can connect to the Autodiscover service.