Hi Will this work ? Linked Mailboxes in resource domain, with user-account in another forest ? Connecting to the linked-mailbox with Outlook (on internal LAN) works. OWA also works, even externally. But Outlook Anywhere doesn't. After starting Outlook, the logon prompt pops up. But no matter how you logon, it will not accept this. Used the Test EmailAutoconfig option on the systray Icon doesn't give any errors.

So you can create a profile using Outlook Anywhere. In what format are the users entering their credentials? Outlook Anywhere definitely works with linked mailboxes. It was actually designed at the request of hosted providers. Missy

Hi, Please try to access the online testing website to diagnose this issue: https://www.testexchangeconnectivity.com/ Then post the information here. Thanks Allen

I used the test website to locate the problem. At first it looked like there was a problem with the Mutual SSL authentication. The client didn't have the same principal name in it's msstd: field. So I changed that on the servers to represent our Wildcard certificate. After that change, the website test runs just fine. No errors. But Outlook2007 still cannot connect. It keeps popping up the login requester. I enter the credentials in mutiple formats. <loginname>@domain.com domain\<loginname> Doesn't matter.

Ehmmmm.... Nevermind. Seem I was to quick to judge after changing the SSL principal name. I now works in Outlook too. FYI, I used : Set-OutlookProvider -Identity EXPR -CertPrincipalName msstd:*.bla.com Thanx for that Website. It's in my Favorites now. Richard