Firewall blocked phpmailer from send email

I am looking for system admin who are expert in cpanel and centos. I have got a problem with my firewall because when I am trying to send the email using phpmailer, it say 554 security failure. I am unable to use open port 587 as i can use only 465. And i am unable to send the email to different smtp using 465 as it get blocked. I can only connect to my own server to send the email. I want to connect many different smtp servers. When I disable the firewall, I can send the email with no problem. If you can help me to fix it on my computer that would be great. I am happy to pay $30 after the problem is fixing. Looking forward to work with you.