How can I open port 587 on a windows VPS running Plesk?
This article applies to 123 Reg Windows VPS hosting
This article will explain how you can open port 587 on your Windows VPS.
Log in to the admin home panel.
Click the Tools & Settings link in the left hand menu.
Click the Mail Server Settings link.
Tick the Switch on message submission option on the Server-wide mail settings page.
This will then activate port 587 on your VPS.