[Hampshire] sendmail oddity

anyone recognise what this means?

It appeared in the /var/log/maillog. It is in consequence of a mail
being sent out by a monitoring process on our server.
Nothing out of the ordinary has appeared in the mailbox set up for
receiving messages issued by the cron jobs on this server.

Jun 11 07:20:03 [host name] sendmail[26730]: STARTTLS=client,
relay=xxxyz.co.uk.inbound10.symantecmail.net., version=TLSv1/SSLv3,
verify=FAIL, cipher=AES256-SHA, bits=256/256

It does not have a numeric tag on it that I can use to relate to other
messages in the log file.

Each occurrence (there are 4 in the last two days, probably
corresponding to four particular emails issued by the monitoring
process but I do not know which) seems co-occur with another unusual
line group:

Jun 11 07:20:02 ws sendmail[26728]: m5B6K2Sx026728:
from=<whoWeSayItsFrom@???>, size=481, class=0, nrcpts=2,
msgid=<200806110620.m5B6K2Sx026728@???>, proto=SMTP,
daemon=MTA, relay=localhost [127.0.0.1]

Jun 11 07:20:05 ws sendmail[26730]: m5B6K2Sx026728:
to=<whoWeSayItsFrom@???>, delay=00:00:03, xdelay=00:00:03,
mailer=esmtp, pri=60481, relay=xxxyz.co....symantecmail.net.
[aaa.bbb.ccc.ddd], dsn=2.0.0, stat=Sent (Backend Replied
[79e6f484.3452849072.199528.00-041.p03c11m034.symantecmail.net]: .0.0
Message recei (Mode: normal))

Jun 11 07:20:05 ws sendmail[26730]: m5B6K2Sx026728:
to=<whoItsReallyFrom@???>, delay=00:00:03, xdelay=00:00:00,
mailer=esmtp, pri=60481, relay=ourSMTPprovider.co.uk.
[912.593.694.968], dsn=2.0.0, stat=Sent (OK id=1K6Jgn-0005P0-6Y)

but that local sendmail tag does not correlate back to any of the
emails sent out by the process

It does not have a numeric tag on it that I can use to relate to other
messages in the log file.

Google has not really enlightened me on this one.

I am assuming that somewhere between our sendmail issuing the message
and one of the recipients, something is complaining but I don't know
how to determine who & what the problem is.
Can anyone enlighten me on where to look?

This is a sendmail installation on a managed machine that I don't have
total control of (if I did, I'd probably replace sendmail with
something else)

Thanks!
victor