Why did an email campaign skip recipients or fail to deliver?

Check the campaign result, provider readiness, sender configuration, and recipient eligibility. Pending, unsubscribed, bounced, inactive, or suppressed contacts may be excluded from sending. Review list health and the reported delivery errors before retrying; do not re-add opted-out contacts just to increase the audience. Sending capacity also depends on provider limits and your plan. Review list cleanup and provider setup.