OK - a “type=Friend” setting means “use the same settings for the inbound that you used for the outbound.” Friend is “PEER + USER”, so you don’t have to fill in the User section on a Friend type connection. You shouldn’t need a “user” section at all if all of the settings are the same AND you are using a “friend” type.
I’m not sure I understand how your PBX is set up if your using an extension to send calls back out into the Internet. The bidirectional trunk you set up for server620 should handle all of your traffic in and out.