Our SME 7.x box apparently had a "problem" last evening.  Sometime around 6:30pm, the "orders" account suddenly stopped getting email.  That account happens to have a consistent stream of mail coming to it -- so it indicates that either the entire server stopped receiving or that account did.
My question is this:  Given the above knowledge, where would I go to check for "lost" emails for that account?  Also, what log file should I be looking in to indicate what happened?