I have been in touch with Tech support about this but they are saying everything is working like it should.

This all started when on NYC3 I installed the one click Ruby on Rails Application gitlab and was not getting email.

I moved over to NYC1 and all mail worked fine with it

Then I created several test droplets on NYC3 with different IP addresses, different versions of Ubuntu as well

I would try to send mail and it would just fail.

For the last round of tests I did the exact same server set up

I fired up a Ubuntu Droplet for 14.04 and only did the following

sudo apt-get install apache2
sudo apt-get install php5 libapache2-mod-php5 php5-mcrypt
sudo apt-get install sendmail

Then I used the following php file for the test

<?php
$to = ’testing@gmail.com’;
$subject = ‘the subject’;
$message = 'hello’;
$headers = 'From: git@mydomain.com’ . “\r\n” .
'Reply-To: webmaster@example.com’ . “\r\n” .
'X-Mailer: PHP/’ . phpversion();

mail($to, $subject, $message, $headers);
?>

Once again NYC3 failed to deliver any mail and NYC1 delivered mail

I have checked the NYC3 IP address to see if it is black listed and it is not

http://mxtoolbox.com/SuperTool.aspx?action=blacklist%3a104.236.247.175&run=toolpage

Here are the log values for the last attempt

syslog

Feb 3 15:50:35 test sendmail[5032]: unable to qualify my own domain name
(test) – using short name
Feb 3 15:50:35 test sendmail[5032]: t13KoZZ5005032: from=www-data,
size=187, class=0, nrcpts=1, msgid=201502032050.t13KoZZ5005032@test,
relay=www-data@localhost
Feb 3 15:50:35 test sm-mta[5034]: t13KoZLw005034: from=www-data@test,
size=390, class=0, nrcpts=1, msgid=201502032050.t13KoZZ5005032@test,
proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Feb 3 15:50:36 test sendmail[5032]: t13KoZZ5005032: to=
testing@gmail.com, ctladdr=www-data (33/33), delay=00:00:00,
xdelay=00:00:00, mailer=relay, pri=30187, relay=[127.0.0.1] [127.0.0.1],
dsn=2.0.0, stat=Sent (t13KoZLw005034 Message accepted for delivery)
Feb 3 15:50:36 test sm-mta[5036]: STARTTLS=client, relay=
gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL,
cipher=ECDHE-RSA-AES128-GCM-SHA256, bits=128/128
Feb 3 15:50:36 test sm-mta[5036]: t13KoZLw005034: to=<
testing@gmail.com>, ctladdr=www-data@test (33/33), delay=00:00:01,
xdelay=00:00:01, mailer=esmtp, pri=120390, relay=gmail-smtp-in.l.google.com.
[74.125.29.26], dsn=5.0.0, stat=Service unavailable
Feb 3 15:50:36 test sm-mta[5036]: t13KoZLw005034: t13KoaLw005036: DSN:
Service unavailable
Feb 3 15:50:37 test sm-mta[5036]: t13KoaLw005036: to=www-data@test,
delay=00:00:01, xdelay=00:00:01, mailer=local, pri=30000, dsn=2.0.0,
stat=Sent
Feb 3 16:00:01 test CRON[5043]: (smmsp) CMD (test -x /etc/init.d/sendmail
&& /usr/share/sendmail/sendmail cron-msp)
Feb 3 16:00:01 test sm-msp-queue[5059]: My unqualified host name (test)
unknown; sleeping for retry
Feb 3 16:01:01 test sm-msp-queue[5059]: unable to qualify my own domain
name (test) – using short name

mail.log
Feb 3 15:50:35 test sendmail[5032]: unable to qualify my own domain name
(test) – using short name
Feb 3 15:50:35 test sendmail[5032]: t13KoZZ5005032: from=www-data,
size=187, class=0, nrcpts=1, msgid=201502032050.t13KoZZ5005032@test,
relay=www-data@localhost
Feb 3 15:50:35 test sm-mta[5034]: t13KoZLw005034: from=www-data@test,
size=390, class=0, nrcpts=1, msgid=201502032050.t13KoZZ5005032@test,
proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Feb 3 15:50:36 test sendmail[5032]: t13KoZZ5005032: to=
testing@gmail.com, ctladdr=www-data (33/33), delay=00:00:00,
xdelay=00:00:00, mailer=relay, pri=30187, relay=[127.0.0.1] [127.0.0.1],
dsn=2.0.0, stat=Sent (t13KoZLw005034 Message accepted for delivery)
Feb 3 15:50:36 test sm-mta[5036]: STARTTLS=client, relay=
gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL,
cipher=ECDHE-RSA-AES128-GCM-SHA256, bits=128/128
Feb 3 15:50:36 test sm-mta[5036]: t13KoZLw005034: to=<
testing@gmail.com>, ctladdr=www-data@test (33/33), delay=00:00:01,
xdelay=00:00:01, mailer=esmtp, pri=120390, relay=gmail-smtp-in.l.google.com.
[74.125.29.26], dsn=5.0.0, stat=Service unavailable
Feb 3 15:50:36 test sm-mta[5036]: t13KoZLw005034: t13KoaLw005036: DSN:
Service unavailable
Feb 3 15:50:37 test sm-mta[5036]: t13KoaLw005036: to=www-data@test,
delay=00:00:01, xdelay=00:00:01, mailer=local, pri=30000, dsn=2.0.0,
stat=Sent
Feb 3 16:00:01 test sm-msp-queue[5059]: My unqualified host name (test)
unknown; sleeping for retry
Feb 3 16:01:01 test sm-msp-queue[5059]: unable to qualify my own domain
name (test) – using short name

mail.err

Feb 3 15:50:35 test sendmail[5032]: unable to qualify my own domain name
(test) – using short name
Feb 3 16:00:01 test sm-msp-queue[5059]: My unqualified host name (test)
unknown; sleeping for retry
Feb 3 16:01:01 test sm-msp-queue[5059]: unable to qualify my own domain
name (test) – using short name

Yet I do the exact same set up on NYC1 and the mail sends perfectly

Here is the log of that effort

Feb 3 20:55:36 testing sendmail[4896]: My unqualified host name (testing) unknown; sleeping for retry
Feb 3 20:55:52 testing sendmail[4899]: My unqualified host name (testing) unknown; sleeping for retry
Feb 3 20:56:36 testing sendmail[4896]: unable to qualify my own domain name (testing) – using short name
Feb 3 20:56:36 testing sendmail[4896]: t141uaal004896: from=www-data, size=187, class=0, nrcpts=1, msgid=201502040156.t141uaal004896@testing, relay=www-data@localhost
Feb 3 20:56:37 testing sm-mta[4901]: t141uack004901: from=www-data@testing, size=396, class=0, nrcpts=1, msgid=201502040156.t141uaal004896@testing, proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Feb 3 20:56:37 testing sendmail[4896]: t141uaal004896: to=testing@gmail.com, ctladdr=www-data (33/33), delay=00:00:01, xdelay=00:00:01, mailer=relay, pri=30187, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (t141uack004901 Message accepted for delivery)
Feb 3 20:56:37 testing sm-mta[4903]: STARTTLS=client, relay=gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL, cipher=ECDHE-RSA-AES128-GCM-SHA256, bits=128/128
Feb 3 20:56:38 testing sm-mta[4903]: t141uack004901: to=testing@gmail.com, ctladdr=www-data@testing (33/33), delay=00:00:02, xdelay=00:00:01, mailer=esmtp, pri=120396, relay=gmail-smtp-in.l.google.com. [74.125.69.27], dsn=2.0.0, stat=Sent (OK 1423014998 p13s$
Feb 3 20:56:52 testing sendmail[4899]: unable to qualify my own domain name (testing) – using short name
Feb 3 20:56:52 testing sendmail[4899]: t141uq3A004899: from=www-data, size=187, class=0, nrcpts=1, msgid=201502040156.t141uq3A004899@testing, relay=www-data@localhost
Feb 3 20:56:52 testing sm-mta[4904]: t141uqbX004904: from=www-data@testing, size=396, class=0, nrcpts=1, msgid=201502040156.t141uq3A004899@testing, proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1]
Feb 3 20:56:52 testing sendmail[4899]: t141uq3A004899: to=testing@gmail.com, ctladdr=www-data (33/33), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30187, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (t141uqbX004904 Message accepted for delivery)
Feb 3 20:56:53 testing sm-mta[4906]: STARTTLS=client, relay=gmail-smtp-in.l.google.com., version=TLSv1/SSLv3, verify=FAIL, cipher=ECDHE-RSA-AES128-GCM-SHA256, bits=128/128
Feb 3 20:56:53 testing sm-mta[4906]: t141uqbX004904: to=testing@gmail.com, ctladdr=www-data@testing (33/33), delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=120396, relay=gmail-smtp-in.l.google.com. [74.125.69.26], dsn=2.0.0, stat=Sent (OK 1423015013 e6si$

I would love some insight as even though I can create droplet after droplet and I can reproduce this every time Tech support claims they are unable to reproduce the issue.

Also the failure is so silent I have wondered if it is a more widespread issue just so new no one has noticed.