I've just completed a server migration from SBS2003 to SBS2008. I'm having a problem on the new server where all but one of the migrated users are having their mail get stuck in the "unreachable domain" queue. Exchange reports that "The mailbox recipient does not have a mailbox database" even though they do have a mailbox and it shows up in the Exchange console. Here's an example:
Identity: SBS2008\Unreachable\2387 Subject: Test mail flow Internet Message ID: From Address: Tim@tigranetworks.co.uk Status: Ready Size (KB): 32 Message Source Name: SMTP:Windows SBS Internet Receive SBS2008 Source IP: 184.108.40.206 SCL: 0 Date Received: 15/01/2010 00:35:59 Expiration Time: 17/01/2010 00:35:59 Last Error: The mailbox recipient does not have a mailbox database Queue ID: SBS2008\Unreachable Recipients: admin@[obfuscated]
Any Exchange experts out there have any idea what might cause this paradoxical situation?