I am configuring availability(free-busy) sharing between to exchange 2007 forests.Forest 1: foo.com smtp addresses bar.comForest 2: lorem.com smtp addresses ipsum.comI have configured galsync to share the smtp namespaces bar.com and ipsum.com.I have configured availability service per: http://technet.microsoft.com/en-us/library/bb125182(EXCHG.80).aspxI added availability namespace for foo.com and bar.com to forest 2, but I am receiving:A cross-forest Availability service that can fill request for mailbox <John Doe>SMTP:JohnD@bar.com could not be found.How can I configure availability sharing for email addresses with domain names that are not the forest name that the trust is based on? Do I simply use the availability configuration for untrusted forests?

We have the same situation. The specific error we are getting is: Event Type: Error Event Source: MSExchange Availability Event Category: Availability Service Event ID: 4001 Date: 7/17/2008 Time: 9:02:38 AM User: N/A Computer: OurCAS Description: Process 5588[w3wp.exe:/LM/W3SVC/1/ROOT/EWS-1-128588074990120491]: Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequestWithAutoDiscover failed. Exception returned is Microsoft.Exchange.InfoWorker.Common.Availability.AutoDiscoverFailedException: A cross-forest Availability service that can fill request for mailbox <User>SMTP:User@domain.com could not be found.. This event may occur when Availability Service cannot discover an Availability Service in the remote forest. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Did you guys get this sorted?I have the same problem but only in one direction! Cheers,Greg

Did you get this resolved? I too have the same issue but it is only one way.

Sorry for the slow response.I did get it sorted in the end but it's a while ago now so I can't quite remember how. Something tells me it was something to do with the certificate as one side was using a public cert and the other an internal cert. I'd need to have a dig around but I stashed the commands I used somewhere.As the client wasn't up for running Outlook 2007 at both ends I did an interorg mailbox move in the end. It was a bit of a pain as we were using an Exchange Archiving tool. Having said that I didn't have many users to move!Cheers,Greg