Thank you Carlos. I added sudo later on and I was able to make changes. However, the installation is not sending e-mail yet. I used the external email service provider "Sendgrid" following the tutorial from this from google cloud on this link https://cloud.google.com/compute/docs/tutorials/sending-mail/using-sendgrid
~$ echo 'Test passed.' | mail -s Test-Email EMAIL@EXAMPLE.COM
~$ tail -n 5 /var/log/syslog
Dec 9 15:22:48 bitnami-edx-dm-725d postfix/cleanup: A5A699836: message-id=<20171209152248.A5A
Dec 9 15:22:48 bitnami-edx-dm-725d postfix/qmgr: A5A699836: from=<.........@bitnami-edx-dm-
725d>, size=362, nrcpt=1 (queue active)
Dec 9 15:22:48 bitnami-edx-dm-725d postfix/smtp: warning: /etc/postfix/main.cf, line 42: over
riding earlier entry: relayhost=
Dec 9 15:22:49 bitnami-edx-dm-725d postfix/bounce: warning: /etc/postfix/main.cf, line 42: ov
erriding earlier entry: relayhost=
Dec 9 15:22:49 bitnami-edx-dm-725d postfix/smtp: A5A699836: to=<EMAIL@EXAMPLE.COM>, relay=smt
p.sendgrid.net[184.108.40.206]:2525, delay=0.37, delays=0.01/0.01/0.35/0, dsn=4.0.0, status=deferred
(SASL authentication failed; server smtp.sendgrid.net[220.127.116.11] said: 535 Authentication fail
ed: Bad username / password).
Not too sure why the password failed
I have used the APIkey and the password generated on sendgrid but it does not work. I generated 3 different ones just to see. Perhaps I am using the wrong pair.
Kindly help with this.