Do you have the full header on that message that did eventually arrive? You're looking for a gap in the times. Or you can post it here as you did the other one - someone here can translate it for you. As soon as I saw the mchsi client, my finger wanted to point in that direction, though from the header above it looks like the mediacom server handed it off to gmail quite promptly. So you would need to see the one that came BACK to see where it got interrupted.
I know it's very frustrating not to be able to count on delivery times. Good luck.
Barb
