Authentication Failure sendng email

Hi guys,

I finally managed to setup CentOS web panel up on digital ocean droplet (and my domain is pointing to it), and everything (contents)  seem to be working, except emails. I am getting an authentication error:

Reporting-MTA: dns; cl.shs.co.za
X-Postfix-Queue-ID: 5A402492787
X-Postfix-Sender: rfc822; info@exsssssp.cf
Arrival-Date: Fri, 24 May 2019 08:58:35 +0000 (UTC)

Final-Recipient: rfc822; deeyc@gmail.com
Original-Recipient: rfc822;deeyc@gmail.com
Action: failed
Status: 5.7.1
Remote-MTA: dns; gmail-smtp-in.l.google.com
Diagnostic-Code: smtp; 550-5.7.1 This message does not have authentication
    information or fails to pass 550-5.7.1 authentication checks. To best
    protect our users from spam, the 550-5.7.1 message has been blocked. Please
    visit 550-5.7.1
    https://support.google.com/mail/answer/81126#authentication for more 550
    5.7.1 information. r10si1527783wmc.53 - gsmtp


Where do I look??? Is it my hostname or setting I forgot to set?

Please assist

Please can anyone assist?

Last piece of puzzle....

Ok its working, but not sending to gmail address, wonder why?

If you are sending emails directly form the control panel, my understanding is that it does not allow SMTP information to be entered so it's attempting to send email without any authentication whatsoever (like account credential information). Gmail and most other providers will not allow you to just send email without authentication as it would invite spam. Maybe ask for this feature to be added to CWP?

I am sendinf email from webmail site, eg.g webmail.website.org

Sorry saw replies only now, al least you guys are responding...I managed to get it to work in Webmail. But have some ssl issues still.