Roundcube + ISPConfig 3

So I followed the tutorial below
The Perfect Server - Ubuntu 16.04 (Xenial Xerus) with Apache, PHP, MySQL, PureFTPD, BIND, Postfix, Dovecot and ISPConfig 3.1
Now, I can send mail locally to myself but I am not able to send it elsewhere, it just says it sent. I've tried sending to an @hotmail.com and an @gmail.com. Also I am not able to send from those addresses to the domain from my website, nothing on my roundcube inbox. I've tried looking multiple places with no solution
No response to the @hotmail.com and no email in that inbox either
with the @gmail.com I get the following:
Final-Recipient: rfc822; email address
Original-Recipient: rfc822; email address
Action: failed
Status: 5.7.1
Remote-MTA: dns; gmail-smtp-in.l.google.com
Diagnostic-Code: smtp; 550-5.7.1 [2601:1c1:8701:6042:3154:dcb3:849e:976f] Our
system has detected that 550-5.7.1 this message does not meet IPv6 sending
guidelines regarding PTR 550-5.7.1 records and authentication. Please
review 550-5.7.1
(link removed due to post requirements) for more 550
5.7.1 information. pl3si14328917pac.22 - gsmtp"

 

set a ptr-record for your ipv6 that matches your mx-hostname.

 

How exactly do I set that up? Kind of new to ispc and I'm also using a no-ip domain at the moment

 

Also in ispc it says my smtp server is offline but everything else is online. Is that normal? I've tried restarting postfix no problems