DEAR generates emails to send to customers. If your organisation is using a custom domain to email customers, DEAR emails can be flagged as spam by the customer's mail server and not appear in a customer's inbox. This is resolved by adding a line to your organisation domain's SPF record. SPF is a mechanism the recipient mail server uses to verify if the DEAR domain (@post.dearsystems.com) is allowed to send a email behalf of another domain.
You will need to add this line to the custom domain SPF record:
When this is done, the email will not be marked as spam by the recipients mail server.