Sendmail weirdness

While sending mail from sendmail to a TLS-enabled smart host I found these logs, despite CACERT option was inserted in sendmail.mc:

Dec  1 04:02:12 cantor sendmail[10263]: STARTTLS=client, relay=smtp.unimore.it., version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-SHA, bits=256/256

(please note the verify=FAIL).

Well, it was solved adding:

define(`confCACERT_PATH',`/usr/share/ssl/certs')dnl

to sendmail.mc.

I double checked CACERT pointed actually to the right CA. Smart Host certificate was issued under the correct CA. So I ended thinking it is just a sendmail oddity.