If you're not sure whats happening with an email, create a small script like this in /usr/local/bin/email-checker.sh


#!/bin/sh
for i in `grep $1 /var/log/mail.log | grep "postfix/smtp" | cut -d']' -f2 | cut -d':' -f2 | sort | uniq`
do
echo "------------------------------------"
grep $i /var/log/mail.log
echo "------------------------------------"
done


And then you can check whats been going on with email-checker.sh who@somewhere.com

Save a bit of trying to grep/less/find etc..