Please provide as much as possible information about your server's setup (network details, domain name, gateway or server-only setup, etc.) , how you send emails (what client, what email client, etc).
Also we will need not only the contents of the last line of a logfile, instead at least the last 40-60 lines should show about the last email sending transaction.
You will also have to look into qmail's current log to find out about the final email delivery, qpsmtpd is only the receiving part of the mail server's delivery process.