Service Desk customer notifications are being marked as SPAM

Issue Summary

Customer notifications about tickets are going directly to SPAM.

Steps to Reproduce

1. Create a Service Desk ticket and make sure it has a request type on it;
2. Comment for customer on the ticket;
3. Check the SPAM inbox of the mailbox.

Expected Results

The customer notifications arrive at the inbox.

Actual Results

Customer notifications are going directly to the SPAM inbox.

Workaround

Whitelist all the Atlassian Domains and IPs in this doc: Atlassian Cloud IP ranges and domains.