Different domain email id not validating

Hi There
By adding valid email addresses, you ensure that only mailboxes owned by the organization will be tested.
To prevent unwanted third party issues we want to make sure that the mailbox belongs to the organization.
If you wish to add a mailbox in a different domain to your assessment you can contact the support team in support@cymulate.com, or reach out to your dedicated customer success engineer.
Make sure you provide the reason for adding an email address in a different domain.
I hope I've answered your question, don't hesitate to ask any other questions you might have, we're always happy to help.