Plesk dedicated server setups - Domain name / Subdomain / Emails

I need you to help me setup two servers : 1. VPS, running Plesk @ OVH provider Task : Fix my webmail / email setup. It doesn't work properly (can't configure any email client for the outgoing / incoming messages), neither the webmail 2. Dedicated server, running Ubuntu/ Plesk @ [login to view URL] provider (dedibox LT) Tasks : > Setup Plesk properly so I can use subdomains creation from Plesk (right now it doesn't work when I use Plesk to create subdomains) > Setup of the https environment on a temporary subdomain name (server side AND magento side) Our server provider [login to view URL] offers this free service through "Let's Encrypt". I need to get it working) > Once our website is finished (1 week later), setup of the https environment on our domain name (server side AND magento side)