Exchange Pickup Directory Transport Size Limit

I ran into a problem on a well established Microsoft Exchange 2010 installation that has implemented the edge server role and Microsoft Forefront Protection 2010 for Exchange Server.

The administrator was trying to release a message from the Froefront quarantine but it wasn't going trough.  A DSN was sent back to the forefront e-mail address with the status of 550 5.3.4 PICKUP.MessageSize; message size exceeds a fixed maximum size limit with the same information under a fail event in the message tracking log.

This system has been up and running for quite some time with a 25 megabyte limit regularly passing messages of that size, but this message was only a little over 10.  It seemed a little strange, I had configured it during implementation and everything seemed in order, but obviously, something wasn't quite right. 

The answer ended up being in the set-transportconfig cmdlet and the maxsendsize argument.  While on the internal exchange organization, that was set way back when, it wasn't done on the edge transport servers.  It didn't seem to be a problem when the server is doing its thing, transferring e-mail to and from the Internet. 

To resolve the problem on Microsoft Exchange 2010 Edge Transport server where pickup directory messages exceed the maximum message size, use set-transportconfig -maxsendsize 25MB (or whatever size you need).