help setting up domains on a mail server

I have a mail server (ubuntu 20.04LTS, postfix, dovecot) with a domain (example [login to view URL]). Mail to that domain ([login to view URL]) is working fine. But I am trying to make mail work for a second domain ([login to view URL]) which will use the mail on the mail server (domain1). I have configured the DNS for [login to view URL] as follows: A [login to view URL] 1.1.1.1. A www 1.1.1.1. MX [login to view URL] [login to view URL] But the mail for domain2 is not working. I need someone to help me get [login to view URL] to work (and domain3, domain4 etc). If you have extensive experience managing a mail server this is an easy job for you. I will provide a virtual server with 2 domains and you will set it all up. You will also document the steps and send me the steps. I will use the steps you provide me to make it all work on my mail server. If it works, you get paid. Again, you need to have extensive experience managing a mail server to do this project.