Yes, it is possible to add external email accounts in SmarterMail for the domains which are not hosted on your Windows VPS
. There are just two steps to accomplish this. Please find them as below:
Step - 1:
Add mail "A" record and "MX" record under the DNS zone of your domain at your DNS provider control panel. You can get record information from this article
Step - 2:
Once the DNS records are added, you can add your domain name in SmarterMail. You can refer to this article
for step-by-step guidance.