Hard Bounce

A hard bounce occurs when an email cannot be delivered due to a permanent reason, such as an invalid email address, non-existent domain, or recipient server that permanently rejects the message. Hard bounces represent delivery failures that will not resolve with retry attempts, making it essential to remove these addresses from email lists immediately. For cold email marketers, managing hard bounces is crucial for maintaining sender reputation and ensuring accurate campaign metrics.

Hard bounces differ from soft bounces, which are temporary delivery failures that might resolve with time or retry attempts. Common causes of hard bounces include email addresses with typos, employee departures that result in deactivated accounts, domain changes or business closures, and recipient servers configured to reject all emails from certain senders or IP addresses. Some bounces that appear ‘hard’ might actually be due to overly aggressive spam filtering rather than truly invalid addresses, but treating them as hard bounces is generally the safer approach for reputation management.

Managing hard bounces requires immediate action and systematic processes. Remove hard-bounced addresses from all email lists immediately – continued sending to invalid addresses signals poor list hygiene to ISPs and can damage sender reputation. Monitor hard bounce rates carefully, as rates above 2% are considered problematic and may trigger deliverability issues. Investigate sudden spikes in hard bounces, which might indicate list quality problems, technical issues, or reputation damage. Use email validation services to verify addresses before adding them to campaigns, especially when importing new prospect lists. Implement automated bounce handling in your email platform to suppress hard bounces automatically. Keep records of bounce reasons to identify patterns that might indicate systematic issues with data sources or list building practices. When possible, attempt to find updated contact information for important prospects who hard bounce, but avoid repeatedly attempting to reach addresses that have bounced definitively.