My Exchange Server application log in the Event Viewer has been constantly throwing the following exception:

The connection to the ADAM instance of the Edge Transport server failed with the exception "The supplied credential is invalid."

I suspect this has been happening since an Exchange Update Rollup or possibly since I installed Exchange 2007 SP1.  What's interesting is that it hasn't affected my mail delivery at all, to my knowledge.  I only stumbled across it because I felt like checking out the app log on a whim.  To verify that the problem exists, run Test-EdgeSynchronization from the PowerShell and you should see that it fails:

The Solution is to re-subscribe your Edge Transport Server connection.  I've already done this in reference to another issue, so I'll just post the link here:

http://bunkerhollow.com/blogs/matt/archive/2008/06/04/reset-edge-transport-server.aspx