I've a problem that has taken a good few hours to fathom - the issue was having moved a handfull of mailboxes / accounts to a new installation of Small Business Server 2011 running Exchange 2010 on a new server (previously on Small Business Server 2008 running Exchange 2007) -
The issue was that external email delivery (receiving & sending) was intermittent or none at all - using MS Remote Connectivity Analyser to test the installation was failing with differing errors from unexpected responses and timing out etc. Having checked and double check the connectors and run the Fix My Network wizard multiple times I eventually decided to turn off MSME on-Access and everything started working with mail coming in and going out as it should.
I then re-enabled VSAPI and retested - still OK, I then re-enabled Transport Scan and all stopped with the Connectivity Analyser failing again.
I've another installation running MSME 8.5 which I'm reluctent to upgrade currently.
Since beging this post I have seen that SP1 version was available and have applied this but with the same issue....