Issue Summary

This is reproducible on Data Center: (yes)

Sending an email to a specific email address using Automation fails.

Steps to Reproduce

1. Create a rule to forward emails from Trello to this specific email address (added on this bug as an internal comment to Atlassian staff due to PII).
2. Trigger the rule.

Expected Results

The email is sent when the rule is triggered.

Actual Results

The email is not sent.

Workaround

Forward from another email that is working with Automation.