CRM 2011: Q4 Service Update and localhost
If, like me, you get consistent ‘Access denied’ error while browsing the “What’s New” activity feed screen, this is because you are using the following Web address: http://localhost/YOUR_ORG
Instead, try using the computer’s Netbios name, for example: http://yourserver/YOUR_ORG it should work!


We are also facing the same problem and this is a bug with Actiivty Feeds solution itself. We are working with MS to get the resolution for the same.
Thank you very much!
Any update to this bug? Would love to try this out but still faced with “access denied” error.