I am trying to connect to a secure outgoing server(pop3 port) of my website to receive all emails to my Gmail inbox. but in my web control panel, the name of the outgoing server is "centos-2gb-nbg1-4" without any domain name or domain suffix in end. I am unable to connect to the server with Gmail when I put the exact name(centos-2gb-nbg1-4) copied from web panel to Gmail. Is anything should be added before/after this outgoing server name before putting in gmail? like this: centos-2gb-nbg1-4.example.com ?
Your outgoing mail server is to send mail out, in your question above you are requesting to receive e-mail to your inbox, so you want to login to your cPanel of your website lookup your Mail settings for your server and look for "Incoming Mail Server" and Port. That is the value you need. To check outgoing, look up your DNS records within your CPanel, it usually is "somevalue.your-domain-name.com" (mail.example.com, or smtp.example.com). Your webhosting provider support team can help with specifics.