Hello, when I created the mail server, it asked me the hostname and I created it as mail.domain1.com. After this stage, I added a few more mail addresses. for example: mail.domain2.com, mail.domain3.com, mail.domain4.com. I have no problem sending and receiving mail, but programs like outlook do not accept mail.domain3.com as the sender server name. I need to create mail.domain1.com in all domains. How do I solve this?