Hello, I have a 3rd party application that uses delegate access to process mailboxes via Exchange Web Services. This application is working fine in a simple Exchange enviroment. However, I'm having problems with this application in an Exchange Resource Forest where Exchange is installed in one forest and the user's login accounts are located in a different account forest. Both the application service account and the user's mailboxes are Linked mailboxes (a mailbox accessed by a user in a seperate trusted forest). Using the Exchange Managment Console, in Recipient Configuration -> Mailbox, using the Mange Full Access Permissions option, I gave the service account full delegate permissions to each user's mailbox. However, when I run the application it comes back with an "object was not found in the store" error. I've seen that error before when permisisons where not granted, so I suspect this might be a permissions problem. The service account authenticates against EWS using credentials from the account forest, could that be part of the problem? Is there an additonal administrative step that I'm missing that needs to be done to make full delegate mailbox access work across the forest (from the account forest to the exchange resource forest)? Thanks, Greg