We have detected that your domain {{ custom_domain.domain }} doesn't have the DNS MX records correctly set up.

Please re-run the MX check on {{ domain_dns_url }} and update them if needed.

Without the MX records correctly set up, emails sent to the {{ custom_domain.domain }}'s aliases
  aren't properly and reliably handled.

Feel free reply to this email if you have any question.

Best,
SimpleLogin team.