At PhotoBiz, we send email notifications for various purposes, such as membership renewals, form submissions, client gallery activities, ecommerce orders, and more. We also use email validation to prevent our email servers from being marked as spam. If an email address rejects our notification email, it's marked as non-deliverable and added to a list of bounced emails. This helps maintain our email server's reputation for not sending emails to invalid addresses. Email addresses can end up on this list for any of the following reasons:

• The email address is full and not accepting additional messages
• The email address no longer exists
• The email address has marked emails from us as Spam
• The email address is down due to a service outage from your email service provider.
• The email address has MX records that are not configured properly

The only way we can remove an email address from our non-deliverable, bounced list is when a client notifies us that they haven't received emails from us and we manually remove the email address from the list. Removing an email address from the non-deliverable list will typically reinstate email notifications, billing emails, etc., If our notification emails are rejected again in the future by the email address, it will end up on the non-deliverable list again and we’d need to manually remove it again.