We have a mixed Exchange 2000/2003 environment. We use an Exchange 2003 front-end server for OWA/OMA. We are having an issue when viewing public folders from the front-end server. When you try to open the contents of certain public folders you get the "HTTP 1.1/ 503 Service is no longer available" message in the browser.Each site has its own root public folder (e.g. New York, Tokyo, Paris, etc). Each site has a back-end Exchange server to house its local public folders, and the replicas are configured appropriately. Users in each office have no problem viewing all of the public folders in the hierarchy through the Outlook client. However, when they try to view public folders via OWA they get the 503 message. The only exception to this is if they try to view a public folder which has replicas on the Exchange back-end server in the same site as the Exchange front-end server (e.g. NY OWA front-end, NY back-end folder replicas can be viewed with no problem from anywhere, Tokyo and Paris back-end folder replicas cannot).I have already followed the steps in:http://support.microsoft.com/kb/840182 and http://support.microsoft.com/kb/823159All is correct according to those articles.There is nothing out of the ordinary in any of the front-end and back-end logs either.Any help on this issue would be greatly appreciated.

FYI, this was resolved by restarting the Exchange services on each affected backend server. I'm assuming that a dismount/remount of the public folder store on each affected backend would have also worked. I still have no idea WHY this occurred, but at least the problem was resolved. Can anyone provide some insight as to why this has occurred?