i did install and configured the sendmail in ubuntu 14.04. In the mail log ( mail.log )file the status is send.

Jul  6 06:22:58 yhchandu sendmail[15117]: v666Mr26015117: from=root, size=0, class=0, nrcpts=1, relay=root@localhost

Jul  6 06:24:41 yhchandu sendmail[15134]: v666Of4Y015134: from=root@ubuntuTest, size=160, class=0, nrcpts=1, msgid=<201707060624.v666Of4Y015134@yhchandu.ml>, relay=root@localhost

Jul  6 06:24:42 yhchandu sm-mta[15135]: v666OfDG015135: from=<root@yhchandu.ml>, size=399, class=0, nrcpts=1, msgid=<201707060624.v666Of4Y015134@yhchandu.ml>, proto=ESMTP, daemon=MTA-v4, relay=ip6-localhost [127.0.0.1]

Jul  6 06:24:42 yhchandu sendmail[15134]: v666Of4Y015134: to=<hemchand.yenumula@gmail.com>, ctladdr=root@ubuntuTest (0/0), delay=00:00:01, xdelay=00:00:01, mailer=relay, pri=30160, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (v666OfDG015135 Message accepted for delivery)

• i herd and that send mail is not passable to do work in Digitalocen.
• If it’s not true, I need manual for installation and configuration of sendmail for ubuntu 14.04