PHP mail function send mails only to Zoho
I have two sites in my droplet that have MX records for zoho mail and have configured postfix according to this video : [https://www.youtube.com/watch?v=7IyXS2wWzwM&list=LL6dywe4eDt-ri9Mn78gum6g&index=2](http://) . PHP function mail work nice and they send emails to my zoho account.
When though I change mail($to, $subject, $message, $headers); the $to variable to let's say firstname.lastname@example.org nothing happens.Probably something has to do with MX records.
Since I have clients that have their own emails I want with a simple PHP form from their site to be able to receive emails to their yahoo gmail or anything else.
Should I install PHP mailer or do something different to postfix?The email services like zoho,gmail etc will do everything I m not going to make my droplet an email server.