This process requires the addition of CNAME in their domain so that customers can get emails from their domain. This is an on-demand process.
Adding SMTP sender email in Safe Senders List:
After adding custom domains, we need to add a custom domain in the safe sender list and domain.
Steps:
Navigate to https://security.microsoft.com/antispam and click on Anti-spam inbound policy (Default).
Flayer will be opened. Scroll down to Allowed and blocked senders and domains.
Click on
Edit allowed and blocked senders and domains
Click on Manager Sender and add <[email protected]> (sender email can be extracted under Company’s SMTP settings) sender.
Click on Allow domains and add <domain.com> domain.
If you would like to unblock automatic picture downloads in email messages for Microsoft O365, then please follow the link.