Postfix Connection Timed out

I used the tutorial below to setup postfix and dovecot on a Digital Ocean server. But I'm getting "Connection Timed out" when postfix/smtp tries to deliver an email to a remote host like gmail or yahoo..

https://www.digitalocean.com/community/articles/how-to-set-up-a-postfix-e-mail-server-with-dovecot

RECEIVING A NEW MESSAGE /var/log/mail.log

Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: Loading modules from directory: /usr/lib/dovecot/modules/auth

Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): lookup service=dovecot

Feb 2 22:33:38 localhost dovecot: auth-worker: Debug: pam(app,189.63.49.XXX): #1/1 style=1 msg=Password:

Feb 2 22:33:38 localhost dovecot: auth: Debug: client out: OK#0111#011user=app

Feb 2 22:33:40 localhost postfix/submission/smtpd[1045]: E9AA724264: client=unknown[189.63.49.XXX], sasl_method=PLAIN, sasl_username=app

Feb 2 22:33:43 localhost postfix/cleanup[1052]: E9AA724264: message-id=

Feb 2 22:33:43 localhost postfix/qmgr[32661]: E9AA724264: from=, size=485, nrcpt=1 (queue active)

Feb 2 22:33:45 localhost postfix/submission/smtpd[1045]: disconnect from unknown[189.63.49.XXX]

Feb 2 22:34:14 localhost postfix/smtp[1053]: connect to mta5.am0.yahoodns.net[98.136.216.25]:25: Connection timed out

Feb 2 22:24:21 localhost postfix/smtp[1013]: connect to mta6.am0.yahoodns.net[98.136.217.202]:25: Connection timed out

Feb 2 22:24:21 localhost postfix/smtp[1014]: connect to gmail-smtp-in.l.google.com[173.194.76.27]:25: Connection timed out

Feb 2 22:24:21 localhost postfix/smtp[1015]: connect to gmail-smtp-in.l.google.com[173.194.76.27]:25: Connection timed out

Feb 2 22:24:21 localhost postfix/smtp[1012]: connect to aspmx.l.google.com[173.194.68.27]:25: Connection timed out

Here is /etc/postfix/main.cf
http://pastebin.com/nHQhh8Bp

/etc/postfix/master.cf
http://pastebin.com/nnJBP9mh

Result from #> netstat -nlptu
http://pastebin.com/PKJX6xC1