Currently customers must reach out to the support team to check if email delivery to an Atlassian account has from blocked. Some common reasons include email bounces while the email address was deactivated by the customer's organisation, or the email address did not previously exist.

It would be nice if there is some indication within the organisation admin hub that shows if a managed account is in a state where they cannot be sent any emails from Atlassian.
And in addition, perhaps allow organisation admins to remove the blocker for email delivery for their managed accounts.