To configure the local Postfix setup to send email through another port, please follow the steps below: 

Configure Postfix to use another port for SMTP:

• Log into the Nodalio Dashboard
• Open the file manager and browse to: /etc/postfix/
• Create a backup of master.cf file (recommended)
• Search for the line labeled: “smtp     inet     n……”
• Below the line you found above, add a new line with the following:
• 5555     inet     n     –     n     –     –     smtpd (5555 – The port you wish to use)
• Save and restart postix by going to the terminal and pasting the following:
• /etc/init.d/postfix restart

Shortcode format in the Nodalio Dashboard:

Shortcode result in the Nodalio Dashboard: