Have setup Exchange federation between two Exchange Organization (no trust exists between domains) both Exchange 2010 sp2. In company A there are 3 Exchange mailbox servers in three different phyical sites again all same version. In company B they can see the free/busy information in 2 of the 3 servers but not the 3rd.
Here is the error they see in Company B
Process 6540: ProxyWebRequest FederatedCrossForest from S-1-5-21-1078081533-1647877149-839522115-52294 tohttps://mail.company.com/ews/exchange.asmx/WSSecurity failed. Caller SIDs: WSSecurity. The exception returned is Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequestProcessingException: System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException:Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
On Company A side I have looked at CAS/Hub Transport/IIS virtural directory settings all appear exactly the same for all 3 boxes. I ran Test-ExchangeFederation and it came up clean. I am at a loss where to look next.
Any ideas?