Bounced emails - email messages that cannot be delivered to a recipient’s email address due to some reasons not depending on our system.

Some of the possible reasons may be:

• A non-existent email address (e.g., the email address could have a typo)
• Mailbox full. If your contact has so many emails in their inbox that they can’t receive any more, your emails will bounce back until there’s space for them. Sometimes, this can mean that the contact is no longer using that email address.
• Spam Filters
• Technical issues on the recipient's server side