When someone creates a Bitbucket account, they are asked to fill in their email, full name and password, and then a verification email is sent to their email address.
In case there is a hard bounce of the verification email due to a typo or misconfiguration of the email account, the user does not get notified.
In case of a hard bounce, instead of displaying the following screen:
show a message to the user that their email was bounced and a suggestion to contact support.
This way the user has feedback that the email delivery failed and can contact support to get help with this issue.