Local move request fails

Running Exchange 2010 SP1.

After initiating a move request I receive the below error:

Message (size 28.77 MB (30,171,299 bytes)) exceeds the maximum allowed size for submission to the target mailbox. You can increase this limit by using the Set-Mailbox cmdlet in the Exchange Management Shell.
Error details: MapiExceptionMaxSubmissionExceeded: IExchangeFastTransferEx.TransferBuffer failed (hr=0x80004005, ec=1242)

What parameter on the mailbox would restrict this?  The only size restriction is on the receive connector and is set to 20MB.  I don't have any restrictions on the mailbox database or the mailbox itself.

Any help would be greatly appreciated.

Thanks,

Dave