It requires MX record pointing to IP address of your hosting product(shared/VPS) with us. For example, if you have windows VPS hosting with us, You are required to add following 2 DNS records at DNS zone of your domain.
i) Record type : MX
  Record Name : [keep it blank]
  Record Data : mail.domainname.com
  MX priority : 10
ii) Record type : A
   Record Name : mail
   Record Data : 127.0.0.1(IP address of your VPS)
After adding above DNS records, you are required to host that domain to your VPS websitepanel or manually from SMarterMail.
[Note :- MX records propagation over the globe will take 24-48 hours.]
Note: It is recommended to verify email list before sending an email campaign.
